Add new data center IT equipment model

First draft of source code to add ElectricEquipment:ITE:AirCooled object to model data center IT equipment.
Hey @mjwitte, did you ever get any more thoughts on this issue?  I'm running performance tests and trying to occupy my time by doing some reviews so I can knock down my Pivotal list a bit.  The swimming pool branch appears nearly ready to merge after I made one commit a few minutes ago, and this one should be close once this issue is resolved.