[JDEV] username case sensitivity

[Aaron McBride]

FYI:
I've been fooling around installing different transports and whatnot, and 
after several hours of pulling my hair I noticed that the MSN transport is 
case sensitive when it comes to usernames (jabber usernames), but Jabber 
itself is not.  The result was that I'd try to login with a different case, 
and Jabber would work, but the MSN transport would give me 407 errors.

I'm not sure what the standard is (my vote is for case insensitivity), but 
it would be nice if all of the transports, and the Jabber server itself all 
worked the same.

-Aaron