Rewrite schema to merge User and Group

This is only a schema change. The app does not
make any sense of this yet.
Adapt models to user/group merge

This has not been tested in the app yet. It does
import and appear to link properly.
Membership -> GroupMembership
Rebuilding and account management seem to work
It starts, and shows the index
templates/group -> templates/account
Fix a bunch of permissions so we can read the index
Index and account page seem to work
HTTP status messages don't render user info

This should help with when the errors are because
of the user info!
Getting cpanels working again
Update a few things for memberships -> membership
Remove duplicate flashed messages
Restore shell and account/repo deletion
Restore more admin controls
Notes
Account meta data, gravatars, and style tweaks
Fix permission tests, and expand slightly
Notes
Expand permission tests
Refactor sshkey commands a bit