Updated OneToOne relationship in ApiKey model to comply with new django 1.5 custom user.
Extracted user handling code to separate function.
Changed default User for get_user_model in backfill_api_keys command.
Changed default User for get_user_model in authentication module.

More precisely, in ApiKeyAuthentication and DigestAuthentication
Merge branch 'master' into django-1.5-support
Changed default username for USERNAME_FIELD in authentication module.

Both in ApiKeyAuthentication and DigestAuthentication.
Merge pull request #1 from reinspijkerman/django-1.5-support

Changed default username for USERNAME_FIELD in authentication module.
Merge branch 'master' into django-1.5-support

Conflicts:
	tastypie/models.py
Removed migrations, they don't work well with 1.5
Update setup.py
Merge pull request #1 from ondrowan/django-1.5-support

Django 1.5 support