Remove unneeded functions
Add support for building addons to ProductionManager

The process fits the current method better than it does in buildManager
(though we'll probably need to deal with moving buildings some time).
Also combined the 2 queues (and a third for the addons) into one using a
triple class (I lament Java's lack of a std::pair equivalent)
Call the super!

Otherwise no buildy
Initial generic upgrades

Needs work to account for the tech/upgrade split (which seems totally
arbitary at first glance)