Break out Geppetto client side setup functions into separate JS module

-GEPPETTO setup functions moved to separate Init module, which returns state variables stored in VARS object.
-Init module also handles attachment of event handlers.
-GEPPETTO#getObjectFromJSONEntity cleaned up. 
-Underscore added to imported scripts and used in a few places for checking for empty objects.
-Removed functions GEPPETTO#mergeEntities, GEPPETTO#divideEntities, because it appears they are not being used.