Better packaging, Python 2.6 compatibility

Packaging:

* Include authors and changelog files.
* Add setup.cfg for binary distribution.

Testing:

* Add testing dependency on unittest2.
* Add Python 2.6 to Travis config.
* Clean up PEP8, PyFlakes, and PyLint violations, add them to Travis
  builds.
Merge pull request #11 from akshayjshah/tests

Better packaging & testing