Add jabber ID field type

I wanted to add a Jabber ID field type, so here 'tis. I began with field_email.inc, and modified several things. Most notable changes are instead of a "mailto:" protocol type in the URI, I've changed it to "im:". Also note that I've got a Jabber presence indicator image as provided by the bot "Edgar".

Example is here for now, although this is a work-in-progress and the URL will change. New file field_jid.inc attached.

I got a function redeclare error the first time I uploaded this field type, so I remarked out the offending function and now its working. (See line 83.) Someone with better coding skills than I can say if that was the right thing to do, because I'm not sure if this will cause problems. But it works perfectly for me.