Use setuptools instead of distribute.

Distribute does not support "install_requires":
<http://stackoverflow.com/a/10686196/113527>.

Since Setuptools and Distribute have merged (see
<http://pythonhosted.org/setuptools/merge-faq.html>), this should not
cause any loss of functionality. Your virtualenvs may need to be
updated, though.
Slightly better Python 3 compatibility.

  * Import parse_qs correctly.
  * Fix syntax error with exceptions.
  * Update access token test to work with both Python 2 and Python 3.
Update classifiers & Travis config w/ Python 3.3.
Update version information.
Make version DRY. See PEP 396.
Merge development branch into master.

Long-lived development branches do not work on Github. Pull requests
based on outdated master code do not help anyone.

In the past, this project has tried to make master usable. Note that
this introduces tons of backwards-incompatible changes, so if you are
currently using HEAD in production, you're going to have a bad time.
Change from module to package.
Fix version string integration.
Fix version change that broke install.

8530d69 broke installation if requests was not previously installed.
This uses the techniques in http://stackoverflow.com/a/16084844/113527
to fix this issue.
Update Travis config.

New layout was causing tests to fail.