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

tools/editor/property_editor.cpp

@@ -1151,6 +1151,7 @@ void CustomPropertyEditor::_action_pressed(int p_which) {
 
 					file->clear_filters();
 
+
 					if (hint_text!="") {
 						Vector<String> extensions=hint_text.split(",");
 						for(int i=0;i<extensions.size();i++) {