Toolbox gadget for new json format

 - Use json data to define possible nodes
 - Use json data to configure node style
 - get rid of handlebars
 - pass json data in the drag context
graph editor: (partially) update to new json format
include non compressed version of jsplumb
lots of cleanups
add missing jquery ui images
update TODOs
tests for jsplumb gadget
no need for "main_graph"
fix DOM element id
update TODO
Support loading graph without nodes coordinates
update TODOs
do not use "node_container"
merge waitForDragover in waitForDrop
more relaxed jslint configuration
jslint
update TODOs
fix issues with changing node id
test for drag & drop
use jquery.simulate for jsonplumb tests