[Wocky] jwgc changes for Athena

[Greg Hudson]

I have been looking for ways to reach out to the existing community of
Zephyr users for our Jabber rollout.  One idea we've considered is a
Zephyr transport for jabber.mit.edu; another option is to provide more
familiar interfaces to Zephyr users.

In furtherance of the second goal, I have pulled down jwgc
(http://jwgc.blathersource.org/) and made changes to make it do GSSAPI
authentication.  I've done the work in
/afs/dev.mit.edu/project/jabber/repos/jwgc.  Since jwgc is a niche
piece of software and is not architecturally very sound, I have not
tried to preserve its generality, and my modified version is only
suitable for connecting to a server which operates very similarly to
jabber.mit.edu.  I will be submitting the patches to source-reviewers
as follows:

  Change #1: Fix a bug in the Unicode conversion code
  Change #2: Fix a bug in the handling of messages with no bodies
  Change #3: Don't request agent info
  Change #4: Allow JID domain to differ from connect server
  Change #5: Refactor stream header creation code
  Change #6: Replace password auth with GSSAPI auth

I expect to deploy this in the next Athena release.  I don't think a
non-Athena deployment is necessary, except possibly for stock RHEL.