Add Production Handling

[kelly-cs]

Currently there is no system to handle the production of units or structures. However, a system has been created to handle the adding/removal of workers from the mineral line in order to build structures.

This could be done with some kind of class, but the biggest issue is going to come from Terran and Protoss production. We will need to account for producing units through different buildings, and factor in the quantity of such buildings. It might be wise to just shove this off to a new class.

Protoss are going to need a way to interact with the Base class, since it has the Chrono boost ability. This ability will be vital for build orders, and it needs to be accessible to all buildings. Therefore, the Base class will likely need a permanent reference to some sort of list of production/tech facilities.

Zerg will be really easy - just subtracting larvae from the bases and adding the units to some sort of queue after confirming the required tech is achieved.