working on the navbar
Threading works, but requires a pretty expensive operation on import

Also doesn't work yet for adding messages later (because they won't be
in the tree I think).
Actually, maybe it will.  This'll need some testing.
updated
Some helper functions mainly for parsing emails
Models have some email parsing in them now (using helpers)
Expandable non-reply part of messages
Merge branch 'threads'
Ignore new mbox file
Added headers table, and got rid of headers field
decode utf8 subjects and from lines