Deprecate RSSContent
Allow more fields to be optional in custom Page admins.

See issue #536. When using a custom Page model and corresponding
admin class and still using the original PageAdminForm, you couldn't
disable the redirect_to and override_url (and less important: active)
fields because the form did not check first if they were in the
fieldset or not.
Merge pull request #537 from Gwildor/master

Allow more fields to be optional in custom Page admins.
Merge branch 'master' into next

* master:
  Allow more fields to be optional in custom Page admins.
Update LICENSE
Merge pull request #545 from feczo/patch-1

Update LICENSE
Add Django 1.7 to Travis
Fix a dumb typo
Merge branch 'master' into next

* master:
  Fix a dumb typo
  Add Django 1.7 to Travis
  Update LICENSE
Drop compatibility with Django < 1.6, less deprecation warnings

Also fixes #548 (RemovedInDjango18Warning regarding get_query_set).
Pillow has been out long enough to drop the old "import Image" fallback
Loading the URL template tag from future is not necessary anymore
Remove more occurrences of loading the URL template tag from future
Do not pass a callable to queryset.filter() (deprecated in Django 1.9)
Expose get_model and get_models without deprecation warnings
ensure_completely_loaded: Put Django 1.7-code first
Fix many deprecation warnings
Fix a few warnings related to not closing opened files
Fix a test; jpeg thumbnails also have .jpg as extension...

How did this work at all before?
Two smallish fixes