Allow the name of the 'bugz' binary to choose the connection used

The goail is to allow a user to create multiple symlinks to the 'bugz'
binary e.g. 'gnomebz', 'kdebz' each corresponding to a connection.

E.g.
Bugzrc:

[gnome]
bugz-alias: gnomebz
...
[redhat]
bugz-alias: rhbz

Command line usage:

$ gnomebz ... # works like "bugz --connection gnome ..."
$ rhbz ...    # works like "bugz --connection redhat ..."

Inspired by busybox style "multicall binaries".