collection.status -> func; indicate coll ahead,behind,conflict

Get collection repo status in function instead of during __init__.
Added calls to functions that analyze collection repo status and
indicate whether it is ahead or behind origin, or if it is in a
conflicted state.
first pass at showing coll state (ahead,behind,etc) in templates
alert if coll repo is behind origin; prevent editing

Notify user if repo is known to be behind origin.
On collection,entity,file edit views, fetch repo and prevent any
editing if repo is behind.
The idea is to prevent as many merge conflicts as possible.
display alert if merge conflict is detected in collection repo