This reverts the following commits partially:
  d157d8a1
  e92d31cf

With buildout 2, indentation is either fully removed (if anything
starts on the same line as '<option-name> =') or preverved (the same
number of leading spaces if stripped). Any use that required these
commits was a misuse. They could even break valid Python.

Not fully tested. With this commit, it is at least possible to
bootstrap SlapOS from Python 3.

This fixes this error:
[2015-04-10 06:28:09,906] INFO         exec self.options['script']
[2015-04-10 06:28:09,906] INFO       File "<string>", line 6, in <module>
[2015-04-10 06:28:09,906] INFO     NameError: name 'env' is not defined

When installing busybox

The script is formatted with self.options dictionnary.

For example :

  [foobar]
  recipe = slapos.recipe.build
  foo = bar
  script =
    print '%(foo)s'

Produces :

  Installing foobar.
  bar

But this can mess up the python code, because there's no
escaping. For example :

  [foobar]
  recipe = slapos.recipe.build
  foo = bar's
  script =
    print '%(foo)s'

Produces :

  While:
    Installing foobar.

  An internal error occurred due to a bug in either zc.buildout or in a
  recipe being used:
  Traceback (most recent call last):
    File "<string>", line 2
      print 'bar's'
                 ^
  SyntaxError: invalid syntax

We can workaround this by using :

  [foobar]
  recipe = slapos.recipe.build
  foo = bar's
  script =
      print '%%s' %% self.options['foo']

But every percent sign has to be escaped. That's why, this
commit introduces :

  [foobar]
  recipe = slapos.recipe.build
  foo = bar's
  format = no
  script =
      print '%s' % self.options['foo']

NB: This commit doesn't remove formating for backward compatibility.

Squashed commit of the following:

commit 275d6e017f06a6a1a038cd1543b3b08f21448178
Merge: 4234290 319c7223
Author: Łukasz Nowak <luke@nexedi.com>
Date:   Thu Sep 8 15:20:10 2011 +0200

    Merge branch 'master' into suggested-improvements

    Conflicts:
    	slapos/recipe/build.py

commit 42342905ad325eefa921de1bc814dd74505ea131
Author: Antoine Catton <acatton@tiolive.com>
Date:   Thu Sep 8 15:12:11 2011 +0200

    Minor: use shlex to parse patch options

commit 7994dcc87afd528ea405c57e2c441b9424018863
Author: Antoine Catton <acatton@tiolive.com>
Date:   Thu Sep 8 15:11:21 2011 +0200

    Buxfix: the patch wasn't send in stdin

commit ee8f324921c7675c764f1c1e05eecf4c1da225f7
Author: Antoine Catton <acatton@tiolive.com>
Date:   Thu Sep 8 12:04:22 2011 +0200

    Use shlex to split command line

Squashed commit of the following:

commit 506d815ff7e1d7b7b5b3c5edcfcea744c5b2201e
Author: Łukasz Nowak <luke@nexedi.com>
Date:   Tue Sep 6 17:54:59 2011 +0200

    Support multiline values.

commit c5d9415000fb072a07164bbdd5c276e53470b265
Author: Łukasz Nowak <luke@nexedi.com>
Date:   Tue Sep 6 17:48:54 2011 +0200

    Fix compatibility layer.

commit 1e301c7ba51060d944fea9ff2be1aba00e3a48b6
Author: Łukasz Nowak <luke@nexedi.com>
Date:   Tue Sep 6 17:41:41 2011 +0200

    Go back to development.

commit 9f523c49
Author: Łukasz Nowak <luke@nexedi.com>
Date:   Tue Sep 6 17:40:00 2011 +0200

    Prepare 0.5 release.

commit fcaf5c04
Author: Łukasz Nowak <luke@nexedi.com>
Date:   Tue Sep 6 17:39:28 2011 +0200

    Be more compatible.

commit 5284491f
Merge: 2d7dc0b3 f15bb155
Author: Łukasz Nowak <luke@nexedi.com>
Date:   Tue Sep 6 17:28:40 2011 +0200

    Merge branch 'master' into cmmi

commit 2d7dc0b3
Author: Łukasz Nowak <luke@nexedi.com>
Date:   Tue Sep 6 17:22:13 2011 +0200

    Explain more about patches.

commit d5df4cdc
Author: Łukasz Nowak <luke@nexedi.com>
Date:   Tue Sep 6 17:18:55 2011 +0200

    Provide better looking patches.

commit c6befb05
Author: Łukasz Nowak <luke@nexedi.com>
Date:   Tue Sep 6 17:15:32 2011 +0200

    Support make-command and make-options.

    Fix configure-command.

commit d2212cb7
Author: Łukasz Nowak <luke@nexedi.com>
Date:   Tue Sep 6 17:04:05 2011 +0200

    Allow to override configure command.

commit 4321b38a
Author: Łukasz Nowak <luke@nexedi.com>
Date:   Tue Sep 6 16:56:49 2011 +0200

    Share applyPatchList with in base class.

commit 4a2ea3b3
Author: Łukasz Nowak <luke@nexedi.com>
Date:   Tue Sep 6 16:56:29 2011 +0200

    Support no md5sum.

commit 2cd36cb7
Author: Łukasz Nowak <luke@nexedi.com>
Date:   Tue Sep 6 16:56:16 2011 +0200

    Show how to patch.

commit 8cd9ea9c
Author: Łukasz Nowak <luke@nexedi.com>
Date:   Tue Sep 6 16:53:45 2011 +0200

    Allow options per patch.

commit 84fea623
Author: Łukasz Nowak <luke@nexedi.com>
Date:   Tue Sep 6 16:48:47 2011 +0200

    Allow patching.

commit 8934eb92
Author: Łukasz Nowak <luke@nexedi.com>
Date:   Tue Sep 6 16:30:46 2011 +0200

    Allow to keep directories in case of error.

    Default is to remove.

commit 74d0b2bd
Author: Łukasz Nowak <luke@nexedi.com>
Date:   Tue Sep 6 16:24:49 2011 +0200

    Allow to have a=b=c, where a is key and b=c is value.

commit 034c2381
Author: Łukasz Nowak <luke@nexedi.com>
Date:   Tue Sep 6 16:17:07 2011 +0200

    Another typo.

commit f5abcde0
Author: Łukasz Nowak <luke@nexedi.com>
Date:   Tue Sep 6 16:15:44 2011 +0200

    Follow fixed typo.

commit 5b950e26
Author: Łukasz Nowak <luke@nexedi.com>
Date:   Tue Sep 6 16:14:35 2011 +0200

    Extract does not need md5sum.

commit 6f725632
Author: Łukasz Nowak <luke@nexedi.com>
Date:   Tue Sep 6 16:14:14 2011 +0200

    Pass md5sum directly.

commit 9f42d22a
Author: Łukasz Nowak <luke@nexedi.com>
Date:   Tue Sep 6 16:13:53 2011 +0200

    Allow to pass empty md5sum.

commit c91fafb1
Author: Łukasz Nowak <luke@nexedi.com>
Date:   Tue Sep 6 16:13:15 2011 +0200

    Fix typos.

commit 8919378d
Author: Łukasz Nowak <luke@nexedi.com>
Date:   Tue Sep 6 16:12:31 2011 +0200

    Fix examples.

Squashed commit of the following:

commit 2d7dc0b3
Author: Łukasz Nowak <luke@nexedi.com>
Date:   Tue Sep 6 17:22:13 2011 +0200

    Explain more about patches.

commit d5df4cdc
Author: Łukasz Nowak <luke@nexedi.com>
Date:   Tue Sep 6 17:18:55 2011 +0200

    Provide better looking patches.

commit c6befb05
Author: Łukasz Nowak <luke@nexedi.com>
Date:   Tue Sep 6 17:15:32 2011 +0200

    Support make-command and make-options.

    Fix configure-command.

commit d2212cb7
Author: Łukasz Nowak <luke@nexedi.com>
Date:   Tue Sep 6 17:04:05 2011 +0200

    Allow to override configure command.

commit 4321b38a
Author: Łukasz Nowak <luke@nexedi.com>
Date:   Tue Sep 6 16:56:49 2011 +0200

    Share applyPatchList with in base class.

commit 4a2ea3b3
Author: Łukasz Nowak <luke@nexedi.com>
Date:   Tue Sep 6 16:56:29 2011 +0200

    Support no md5sum.

commit 2cd36cb7
Author: Łukasz Nowak <luke@nexedi.com>
Date:   Tue Sep 6 16:56:16 2011 +0200

    Show how to patch.

commit 8cd9ea9c
Author: Łukasz Nowak <luke@nexedi.com>
Date:   Tue Sep 6 16:53:45 2011 +0200

    Allow options per patch.

commit 84fea623
Author: Łukasz Nowak <luke@nexedi.com>
Date:   Tue Sep 6 16:48:47 2011 +0200

    Allow patching.

commit 8934eb92
Author: Łukasz Nowak <luke@nexedi.com>
Date:   Tue Sep 6 16:30:46 2011 +0200

    Allow to keep directories in case of error.

    Default is to remove.

commit 74d0b2bd
Author: Łukasz Nowak <luke@nexedi.com>
Date:   Tue Sep 6 16:24:49 2011 +0200

    Allow to have a=b=c, where a is key and b=c is value.

commit 034c2381
Author: Łukasz Nowak <luke@nexedi.com>
Date:   Tue Sep 6 16:17:07 2011 +0200

    Another typo.

commit f5abcde0
Author: Łukasz Nowak <luke@nexedi.com>
Date:   Tue Sep 6 16:15:44 2011 +0200

    Follow fixed typo.

commit 5b950e26
Author: Łukasz Nowak <luke@nexedi.com>
Date:   Tue Sep 6 16:14:35 2011 +0200

    Extract does not need md5sum.

commit 6f725632
Author: Łukasz Nowak <luke@nexedi.com>
Date:   Tue Sep 6 16:14:14 2011 +0200

    Pass md5sum directly.

commit 9f42d22a
Author: Łukasz Nowak <luke@nexedi.com>
Date:   Tue Sep 6 16:13:53 2011 +0200

    Allow to pass empty md5sum.

commit c91fafb1
Author: Łukasz Nowak <luke@nexedi.com>
Date:   Tue Sep 6 16:13:15 2011 +0200

    Fix typos.

commit 8919378d
Author: Łukasz Nowak <luke@nexedi.com>
Date:   Tue Sep 6 16:12:31 2011 +0200

    Fix examples.

Additionaly support slapos_update_promise

pipeCommand allows to simulate shell pipes.

failIfPathExists allows to stop in case of path which exists.

Read md5sum passed to method directly.

This reverts commit 94b519d8.

This reverts commit 667ec876.