Add new data center IT equipment model

First draft of source code to add ElectricEquipment:ITE:AirCooled object to model data center IT equipment.
It can...but my gut is telling me to not recommend that yet.  The compiler will automatically generate a default constructor for you under most conditions, but there are gotchas.  As we move to having object orientation, I think it would be better to keep the default constructor explicitly user-defined.