Remove testutils.assert_raises

Adds dependency on unittest2

Fixes #41
Rename all .txt files to .rst, so that these are rendered by GitHub.
Merge pull request #53 from mcepl/rename_to_RST

Rename all .txt files to .rst, so that these are rendered by GitHub.
Update README.rst

Fix broken doc links
Merge pull request #52 from mcepl/fix_README

Update README.rst
Merge pull request #48 from mcepl/remove_assert_raises

Remove testutils.assert_raises
Complex PEP8ization

* star imports in rope/base/pynamesdef.py and rope/base/ast.py
* many too complex methods/functions

Fixes #46