Add pool of GitHub objects, one per authorized username
Update objects and their related with simple methods
Pep8 github.py
Add ability to pass headers on Executable github objects

And also return non-json content.

Both updates are useful to get content fetched in a raw or html format
Models can have a different Accept header that "json"
Add a way in github.py to return response headers

(and transparently change the way request headers are accepted)

If the user wants to get the response headers, he must pass a dict for
the "response_headers" argument of the call. This dict will be updated
once the request finished, with the whole list of request headers
Retrieve response headers, and change the way to pass request headers
Fetch data while github tell there is a next page
Fetch a list with varying parameters

Example: github cannot fetch all issues, but only open OR closed.
Now we can fetch_many with vary={'state': ('open', 'closed')} and the
whole fetch will be done.
Add fetch_all methods for GithubObject and subclasses
Add __str__ and __unicode__ methods on core.models
Enhance saving of related lists when fetched
Add doc about the vary parameter of fetch_many
Ability to set default values for one not given by github

Ex: when fetching an issue, if we know its repository, set it as a default to avoid guessing it from an url, and doing extra sql requests
Always save fetched_at, not only on... creation !
Tell git to ignore db and sublimes files
Enhance save while fetching to do less sql queries

Also correct some errors when saving some fields (is_organization and
is_pull_request)
Set default reopsitory and issue on some models for the fetch method
Speed up finding of a label type for a label
Only update objects in db if there is something new from github