-Many fixes to VisualScript, fixed property names, etc.

-Added ability to set/get a field in GetSet, as well as assignment ops
-Added a Select node
-Fixed update bugs related to variable list and exported properties, closes #9458

editor/plugins/script_editor_plugin.h

@@ -106,6 +106,7 @@ public:
 
 	virtual void set_tooltip_request_func(String p_method, Object *p_obj) = 0;
 	virtual Control *get_edit_menu() = 0;
+	virtual void clear_edit_menu() = 0;
 
 	ScriptEditorBase() {}
 };
@@ -363,6 +364,8 @@ public:
 
 	bool can_take_away_focus() const;
 
+	VSplitContainer *get_left_list_split() { return list_split; }
+
 	ScriptEditorDebugger *get_debugger() { return debugger; }
 	void set_live_auto_reload_running_scripts(bool p_enabled);