This fix was already done by Roman. But the escape_data dict cache was
posing problem in specific complex case. (Notably in
collective.recipe.template tests).
To keep the last fix, we would have to change every method of Options
class.

This fix does not use escape_data dict cache. This way, it allow
a simple working fix with minimal impact. Not breaking backward
compatibility.

This reverts commit ef1a217bbb2b0abd21a630e6154ff8dc5e968caa.

Squashed commit of the following:

commit ef1a217b
Author: Romain Courteaud <romain@nexedi.com>
Date:   Tue Oct 11 10:01:10 2011 +0200

    Escape $$ character to $.

    Do not escape when fetching dependency values.

commit 8232c9aa
Author: Antoine Catton <acatton@tiolive.com>
Date:   Mon Oct 10 09:57:12 2011 +0200

    Add tests for dollar sign escaping

Avoid unnecessary conflicts during merges.

git-svn-id: http://svn.zope.org/repos/main/zc.buildout/trunk@123007 62d5b8a3-27da-0310-9561-8e5933582275

git-svn-id: http://svn.zope.org/repos/main/zc.buildout/trunk@123006 62d5b8a3-27da-0310-9561-8e5933582275

git-svn-id: http://svn.zope.org/repos/main/zc.buildout/trunk@122990 62d5b8a3-27da-0310-9561-8e5933582275

paths to set up a custom interpreter part that has the distributions
or parts in the path. For example::

python bootstrap.py init BeautifulSoup


git-svn-id: http://svn.zope.org/repos/main/zc.buildout/trunk@122989 62d5b8a3-27da-0310-9561-8e5933582275

Changed a spawn call to a subprocess call to avoid some spurious output.


git-svn-id: http://svn.zope.org/repos/main/zc.buildout/trunk@122988 62d5b8a3-27da-0310-9561-8e5933582275

git-svn-id: http://svn.zope.org/repos/main/zc.buildout/trunk@122981 62d5b8a3-27da-0310-9561-8e5933582275

git-svn-id: http://svn.zope.org/repos/main/zc.buildout/trunk@122980 62d5b8a3-27da-0310-9561-8e5933582275

According to specification networkcache usage in buildout shall be fully
optional. The missing part was to make bindings immune on slapos.libnetworkcache
API changes or its internal errors.

Squashed commit of the following:

commit 79064a17
Author: Łukasz Nowak <luke@nexedi.com>
Date:   Thu Sep 22 13:12:54 2011 +0200

    Proof that bindings to nc are immutable.

commit b9795d85
Author: Łukasz Nowak <luke@nexedi.com>
Date:   Thu Sep 22 11:35:38 2011 +0200

    Immune buildout on any networkcache issues.

    As fallback shall be always possible make binding really immune to any problems
    in networkcache including name errors, api changes, syntax errors, etc.

commit ff3a32b9
Author: Łukasz Nowak <luke@nexedi.com>
Date:   Thu Sep 22 11:22:10 2011 +0200

    Show how networkcache is installed.

commit eeaccfc2
Author: Łukasz Nowak <luke@nexedi.com>
Date:   Fri Sep 2 11:14:49 2011 +0200

    M2Crypto is not needed anymore.

Squashed commit of the following:

commit 2c3b7f2f859f15c08f856a2d58806d86d0020990
Author: Łukasz Nowak <luke@nexedi.com>
Date:   Wed Aug 31 16:36:18 2011 +0200

    Prove that keys are passed to libnetworkcache.

commit c380b1ea414c28478d5c2049752b6dcedb0c808f
Author: Łukasz Nowak <luke@nexedi.com>
Date:   Wed Aug 31 15:42:05 2011 +0200

    Support shacache and dir SSL based auth.

Thanks to (un)patching urllib before importing zc.buildout.download no more
M2Crypto cluttering is done.

This allows complex library usage in bootstrap process.

Certificates to check content are provided as inline strings.

also convert those certificates correctly.

Convert buildout emptiness to Nones.