Initial import of jabber file receive and DCC send support. This introduces
only a few changes to bitlbees code, mainly the addition of the "transfers"
command.
This is known to work with Kopete, Psi, and Pidgin (formerly known as gaim).
At least with Pidgin also over a proxy. DCC has only been tested with irssi.
IPV6 is untested but should work.
Currently, only receiving via SOCKS5BYTESREAMS is implemented. I'm not sure if
the alternative(in-band bytestreams IBB) is worth implementing since I didn't
see a client yet that can do it. Additionally, it is probably very slow and
needs support by the server as well.
