Populates Issue's repository from URL when not in response.
Minor enhancements to rate limiting information

If rate limiting information hasn't been retrieved already, it will be checked
rather than just assuming 5000 requests remaining of 5000.

Add an additional attribute `rate_limiting_resettime` to reflect github's new
X-RateLimit-Reset header. This integer value is a unix timestamp.

RateLimiting unit test updated accordingly.
Adding since, until parameters to Repository.getCommits()
Merge branch 'develop' into topic/KnowYourParent
Update readme
Merge branch 'topic/KnowYourParent' into develop
Split manage.sh test
Fix readme :-D
Be explicit about test coverage lacking in Notification.py
Merge branch 'topic/ImproveRateLimiting' into develop
Update readme
Improve coverage
Merge branch 'topic/AddParamsToRepositoryGetCommits' into develop
Update readme