Repo, Issue, Gist and Account equality
Add alternate version attribute.

This will help with comparisons similar to:

if github3.__version_info__ < (0, 6, 0):
    foo
else:
    bar
One-liner to add a 'since' parameter to iter_all_repos (github had it,
I needed it to avoid spending days rerunning after bugfixes).
Merge remote-tracking branch 'github/pr/76' into develop
Add equality testing to Keys too.
Merge remote-tracking branch 'github/pr/80' into develop
Use tests_require instead of install_requires

Previously some dependencies for unit testing were mixed
with other dependencies in install_requires option.

Distribute (was setuptools) provides tests_require option
to describe dependencies only for testing, so we'd better
to utilize it.  More over it doesn't require administrator
permission even if you aren't using virtualenv --- it simply
unpacks dependencies on working directory instead.
Add equality testing methods to most objects

Closes #69
Merge remote-tracking branch 'github/pr/82' into develop
Add equality testing to Threads

Account for this change github/developer.github.com@34a7456b687
s/clelan/clean
Store number of additions and deletions on a Pull Request
Merge remote-tracking branch 'github/pr/84' into develop
First pass at documenting how to write tests
Almost forgot @myusuf3
Removed 'Etag' and 'Last-Modified' from the tuples returned by
Repository.iter_languages.