Snapshot of work to refactor the system data model. I've decided that I really can't bury the concept of modules from the 2004 prototype and have any prayer of achieving the sort of composability demo I desire. I was sort of hoping to fudge the line between systems and modules but I'm becoming re-acquinted with my previous agonizing on the subject and we're going with modules as a first class modeling concept in SCDL 2013.