Quick and dirty Core implementation of the new protocol

Next up: Implementing conversion
Added java to protobuf-regen.sh
Now ignoring presence updates

This should fix all the conflict messages while you're in a group
New protocol awesomeness

@sohalt work for you: pls implement ConversionFramework

@Vinpasso that's how we're gonna do it, you can start working with the protocol now (quoting @sohalt: "hopefully")

@main-- implement the core you idiot