Break out Geppetto.js setup functions into separate module

-GEPPETTO setup functions moved to separate Init module, which has an "initialize" function that returns state variables stored in VARS object.
-Init module also handles attachment of event handlers.
-GEPPETTO#getObjectFromJSONEntity cleaned up. 
-Underscore added and used in a few places.
-Fixed a few implicit global variables (missing "var" declarations)
-Removed functions GEPPETTO#mergeEntities, GEPPETTO#divideEntities, because it appears they are not being used.

-Removes GEPPETTO#setMouseClickListenter, GEPPETTO#removeMouseClickListenter because they aren't being used (Let me know if you want them left in.)