FIX Back port of bug fixes and enhancements from silverstripe.org/forum
Merge pull request #80 from camfindlay/backports-ssorg

FIX Back port of bug fixes and enhancements from silverstripe.org/forum
ENHANCEMENT fixed hardcoded subscription links and bugs for sub/unsub actions.
Merge pull request #75 from camfindlay/subscribefixes

ENHANCEMENT fixed hardcoded subscription links and bugs for sub/unsub
Adding SQLite to Travis builds.
Remove pgsql support.
redirect to show on not logged in
Fixed Avatar field

Changed to FileField rather then UploadField. The latter doesn't work
properly on the frontend.
Merge pull request #86 from halkyon/redirect_changes

Better handling of errors if not logged in. Redirect if no form.
Merge pull request #87 from halkyon/upload_field

Fixed Avatar field
Improved PHP version coverage for travis tracking only 3.1 core
Updated master branch travis config to test against master and 3.1 cores.