I committed some basic diplomacy. Nothing fancy, more or less AoK style diplomacy.
There has been some discussion (with lots of suggestions/areas for improvement) on irc with erik and k776, to first get a basic version and extend that later on. (Maybe I'll make a new ticket for that)
I believe Taunts should probably get a ticket of its own.
If tributing units is still wanted, we should probably do the same.
We don't have any territories (as in a early version of the design document) so that point is moot.