removed documentation about obsoleted 'per section python'

Documentation fix: Mac OS -> Mac OS X and correct short string.

The source code maps `macosx` to `'darwin' in sys_platform`, so this is definitely Mac OS X and not the *old* Mac OS.

Merge branch 'reinout-future-import-scripts' of https://github.com/reinout/buildout into reinout-reinout-future-import-scripts

Merge branch 'refactor-pickedversions' of https://github.com/jaap3/buildout into jaap3-refactor-pickedversions

Removed data_files from setup.py, which was installing README.rst in current directory during installation

Bump version to indicate change in dependencies.

We don't need to juke faking setuptools (or not) when we are using
setuptools rather than distribute.

Even if distutils / setuptools gives it to us more than once.

Use that normalizer everywhere.

My doctest / renormalizer fu is not strong enough to deal with the
changes to output:

- setuptools now has dependencies, and emits output to add them as
  'find-links'.  I tried adding an 'adding_find_link' renormalizer,
  but it doesn't suppress the output.

- Other failures due to merge tweaking APIs, etc.  Again, I'm not
  competent to fix them in the doctest / renormalizer world:  they make
  my head hurt.

Forward port of http://svn.zope.org/zc.buildout/trunk/src/zc/buildout/buildout.txt?rev=127336&view=diff&r1=127336&r2=127335&p1=zc.buildout/trunk/src/zc/buildout/buildout.txt&p2=/zc.buildout/trunk/src/zc/buildout/buildout.txt

See http://svn.zope.org/zc.buildout/trunk/?rev=127336&view=rev; this fix was made after buildout 2 was branched off.

This includes renaming `store_picked_versions` to `store_required_by`
to better signify its intent and adding `get_picked_versions`
to `zc.buidlout.easy_install`.