Implemented __deepcopy__ to avoid infinite recursion in __getattr__ while deepcopying a Choices instance
Added deepcopy test
Merge branch 'master' into fix-choices-deepcopy

* master: (23 commits)
  only accepting iterables to the when field
  adding 'when' parameter to MonitorField
  Update AUTHORS and changelog.
  Add test to verify get_subclass() on QuerySet
  Refactor to make sure get_subclass() is on QuerySet
  Fixed indexing into Choices so its useful.
  Fix bug with child/grandchild select_subclasses in Django 1.6+; thanks Keryn Knight.
  fixed code block
  Bump version for dev.
  Bump version for 1.5.0 release.
  Add option-groups capability to Choices.
  Add Changelog note about Choices equality/addition.
  Added tests to improve coverage
  Alphabetised authors
  Removed redundant inequality method on Choices
  Moved documentation for Choices field to the right place
  Corrected typo
  Added self to Authors file
  Added equality methods to Choices objects, and overrode + for Choices for easy concatenation with other Choices and choice-like iterables. Also wrote tests for them, and extended the readme to reflect this
  Fix typo noted by @silonov
  ...

Conflicts:
	model_utils/choices.py
Merge branch 'fix-choices-deepcopy'

* fix-choices-deepcopy:
  Added deepcopy test
  Implemented __deepcopy__ to avoid infinite recursion in __getattr__ while deepcopying a Choices instance
Update AUTHORS and changelog.