Refs #340: Remove forms.css

I clicked around our contrib app pages that have forms and looked at
what styles were applied (using Chrome Inspect Element) and didn't see
anything from forms.css being used. I conclude that bootstrap is
overriding everything we were setting in forms.css, so it's redundant.
Refs #340: Move old stylesheets to locations app

- Stop loading old stylesheets in base RapidSMS template
- Move the old stylesheet files to the locations app
- Load the old stylesheets from the locations app's base template
- Modify the table styling in a few other contrib apps' code to take
  advantage of bootstrap
- Add a backwards incompatibility note to the 0.15 release notes.
Refs #382: Accept single space after keyword

In KeywordHandler:
- rework regex with comments
- add test for single space
- add some other tests too
- update the doc
Suggest PyPI classifiers and license
start 0.16 release on develop
Refs #382: Improve readability of regex
Add to suggested classifiers
Merge branch 'feature/suggest-pypi-classifiers-and-license' into develop
Revert changes to releases/0.15.0.rst
Merge branch 'develop' into feature/340-drop-forms.css
Update releases/0.16.0.rst
Merge branch 'feature/340-drop-forms.css' into develop
Merge branch 'feature/382-keywordhandler-accept-space' into develop
add links to external python guides
Merge pull request #403 from rapidsms/feature/add-links-to-external-guides

add links in contributing docs to external python guides
fixes a bug in the db router that doesn't properly iterate
through the transmission groups.
use django 1.5 staticfiles template tags
Patched DatabaseRouter to fix #412
update tox version to fix travis builds
Merge pull request #415 from rapidsms/feature/fix-travisci

Fix Travis CI builds