Add spam prevention features. Bug 843789.

- Added general use honeypot widget
- Added CSRF to /firefox/partners & /about/partnerships
- Added labels to /firefox/partners form
- Added required field to /collusion form
- Updated /apps/firefox/tests.py to play with updated proxy
Merge pull request #768 from jpetto/bug-843789-spam-prevention

Add spam prevention features. Bug 843789.