Voice and Video GSoC Project

[Maiku]

It's been a while since my last update so here goes. The past few days
I've been figuring out how to refactor the voice and video code in
libPurple to support any number of different combinations of voice and
video sessions. Pidgin doesn't need to support all the combinations,
but I thought it important, libPurple being a library and all, to
support such flexibility. The other advantage to this is that I'm
making it so that the code to create a video session is almost
identical to creating an audio session. Previously, it was going to
have a bunch of function pairs, almost completely identical, one for
audio and one for video each.

I've also been working on decoupling the Jingle code from jabber.c,
modularizing it to make it easier to handle multiple content types in
the same Jingle session, and keep the possibility open for
implementing Jingle file transfers. In doing this, I'm writing some
functions to make creating Jingle packets much more simplified and
hopefully have less duplicated code. Through studying the XEPs more
I've noticed a few places the Jingle code still deviates from the
standard, so I'm fixing that up as well.

-Maiku