added csrf module
removed old csrf code, added convenience function for resetting session csrf secret
replaced uuid with crypto/rand
Merge remote-tracking branch 'origin/develop' into feature/csrf
Merge remote-tracking branch 'origin/develop' into feature/csrf
separate revel imports, naming cleanup, no tokens if CORS, access to raw token in renderargs
fixed broken CSRF tests, added exemptions, general code cleanup
make exempt paths case insensitive
Merge remote-tracking branch 'origin/develop' into develop
Merge pull request #606 from iamjem/develop

CSRF Support