added support for multi-party voice chat

Ignore-this: 21ba7f4219068a9268f7bcc5f3912ef2

Since i don't have a mixer, why not use the operating system!
Simple solution is to simply create a speaker for each person in the conversation and
play the sound from that person from that speaker. Duh!

darcs-hash:20140805222111-c21fe-871fc3a10016f8fdf5f113b1300de88f9db42703