Add support for player emotes

[jleclanche]

To use Joust as a kettle frontend, we'll need support for sending and receiving emotes. I'm also thinking of adventure boss emotes.

For now let's not worry about the actual packets, but I'd like us to add support for a speech bubble + sound accompanying it.

[azeier]

We could consider adding this for replays, too. Just not in an interactive fashion.

Something like this:

• Start of the game (both players): 90% 'Greetings', 10% 'Threaten'
• Player has lethal: 90% 'Well Played', 10% 'Greetings'/'Sorry'
• Opponent when player has lethal: 90% 'Well Played', 10% 'Thanks'