Updated Django versions to match requirements
Removed custom python_2_unicode_compatible. Closes #2183
Removed custom StringIO, force_text, smart_text compat
Removed custom urlparse compat
Removed unused compat code
Merge branch 'master' of github.com:tomchristie/django-rest-framework
Removed unused imports, pep8 fixes, typo fixes
Merge pull request #2200 from maryokhin/master

Clean up compat code