remove logging statements
Added memcache for users and notifications
Allow for edit_tree and add_tree notifications
Issues with form
logging for updated cookiew
Merge branch 'authentication_fix'
Remove references to get_user_by_session

Because we are only interested in the user_id which is stored in
the cookie, we will access the data in the cookie directly. This
has multiple beneficial effects.

1. We no longer go to the datastore for user information

2. We no longer trip the mechanism that updates the UserToken

3. We are basing the logged in status on the existence of the
user_id, not on the existence of a session object (which could
be corrupt)
invalidate memcache when a new tree is created