Test correct versions of Django

It looks like our versions ranges weren't correct.
Change assertRaises for Python 2.6 compatibility
Bumping the version number.
Changelog for 2.0.2.
Merge branch 'release/2.0.2' into develop

* release/2.0.2:
  Changelog for 2.0.2.
  Bumping the version number.
Add IMAGEKIT_DEFAULT_FILE_STORAGE setting
Merge branch 'develop' into ik-next

Conflicts:
	imagekit/__init__.py
	imagekit/conf.py
	imagekit/generators.py
	imagekit/models/fields/files.py
	imagekit/utils.py
	tests/core/tests.py