Use the builtin "open" on Python 3.
Tox: use git urls for py3 versions of smartypants and typogrify

+ This make it easier to use tox with py3: no need to checkout manually
  typogrify and smartypants repos and use tox's distshare.
+ Remove feedgenerator as it is already a dependy for pelican.
Update version requirement with feedgenerator 1.6

feedgenerator 1.6 changes the order of attributes in feeds, so we must use this
version to have consistent functionnal tests.
Update tests output with feedgenerator 1.6

feedgenerator 1.6 includes a change to write feed attributes in a consistent
order between py2.7 and py3.3.
Include feeds and mkd files in the dist package.

This files are needed to run the tests.
Drop python 3.2 support and move to python 3.3.

Jinja 2.7 (released 2013-05-20) supports only Python3 >=3.3 so it is time to
drop Python 3.2 and move to 3.3
Merge pull request #907 from saimn/py3k

Drop python 3.2 support and move to python 3.3
tests/test_readers.py: Remove redundant 'expected' check in AdReaderTest

AdReaderTest.test_article_with_asc_extension() has had duplicate
checks on the expected metadata since it was created by 49f481e3 (Add
asciidoc reader support, 2013-10-28).  This commit removes the
duplicate entry.