URGENT: _extension needs to be settable

  attribute to be settable and it wasn't.

Run docs doctests in travis

I need this for some work I'm about to do so...

Yay, doctests work in travis

Also cache eggs

Because sphinx doesn't work with it.

Also, I wonder if scripts can be multiple lines.

Transaction meta data cleanup

Convert to unicode if bytes are given.

  defined to be text (unicode) as apposed to Python the ``str`` type.

- Added the ``extended_info`` transaction attribute which contains
  transaction meta data.  (The ``_extension`` attribute is retained as
  an alias for backward compatibility.)

  The transaction interface, ``ITransaction``, now requires
  ``extended_info`` keys to be text (unicode) and values to be
  JSON-serializable.

Run decorator, a simpler alternative to attempts

Fix #19 attempts didn't stop on success

It's nice if docs are tested, but doctests shouldn't pollute docs.

Uses fix from https://github.com/zopefoundation/transaction/pull/20/files
but different test changes.

Should fix build failures on slightly-older setuptools installations,
e.g.: http://jenkins.pylonsproject.org/job/transaction/53/console.

Update URL in setup.py Thanks!

Corrected ITransaction: removed beforeCommitHook and 2 misplaced 'self' parameters

Corrected ITransaction: removed beforeCommitHook (no longer implemented) and two misplaced 'self' args.

Restore display of missing lines.

Add new testing dep, 'mock' for coverage env.