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.h

@@ -20,6 +20,8 @@ friend class VisualScript;
 
 	void _set_default_input_values(Array p_values);
 	Array _get_default_input_values() const;
+
+	void validate_input_default_values();
 protected:
 
 	virtual bool _use_builtin_script() const { return false; }
@@ -300,6 +302,7 @@ public:
 
 	virtual bool can_instance() const;
 
+	virtual Ref<Script> get_base_script() const;
 	virtual StringName get_instance_base_type() const;
 	virtual ScriptInstance* instance_create(Object *p_this);
 	virtual bool instance_has(const Object *p_this) const;