Members can send each other private messages.

Problems:
Notifications controller test fails on redirecting, but seems to work fine in practice
Send Message button doesn't look nice on page
Fix test failure on redirect

The "create" method was never being called. Removing the sender_id
parameter fixed that. Routing problem, maybe?
Merge pull request #6 from pozorvlak/private_message

Fix test failure on redirect
a few small tweaks to the views
Cleaned up controller for notifications.

Removed json from notification, since it's a bit risky and we don't really need it.
using cancan more correctly, fixed broken tests
Merge branch 'dev' of github.com:phazel/growstuff into private_message
Merge branch 'private_message' of github.com:phazel/growstuff into private_message

Conflicts:
	spec/controllers/notifications_controller_spec.rb
Merge pull request #161 from phazel/private_message

Private message