New bugzilla email interface

[Daniel Berlin]

I've integrated gnome's experimental bugzilla email interface.
I've moved the gnats converter interface to gnats@dberlin.org.

It supports querying /sending/modifying/closing bugs from email.

Please ignore any reference to <bugid>@ support. I've not set up the 
virtual domains necessary to make this work.

Just use bugmail@dberlin.org instead.

send the word "help" to get a list of commands and how to use them.