More visual script work

-Block switches to 2d/3d editor if editing visual script
-Added cast node in flow control
-Added ability to do RPC in visual script
-Comment nodes
-Fix bug with inverted cable in connecting backwards
-Copy and paste nodes, including from different scripts

modules/visual_script/visual_script_yield_nodes.h

@@ -9,6 +9,7 @@ class VisualScriptYield : public VisualScriptNode {
 public:
 
 	enum YieldMode {
+		YIELD_RETURN,
 		YIELD_FRAME,
 		YIELD_FIXED_FRAME,
 		YIELD_WAIT