Abolish xmatch in favor of plugin prefix
Abolish xmatch in favor of plugin prefix

I no longer need to shoehorn users into a particular prefix if they use
xmatch, nor even provide xmatch at all.

Also since we're changing all the xmatch lines anyway, I'll change from
`:sym => val` to `sym: val`

petertseng/cinch-game_bot,petertseng/cinch-game-bot