Shifts "Help" menubar entry in world editor to use new API structure as example/test
Removes extraneous 'MainEditor'
Adds EditorCore module
Moved Menubuilder to EditorCore module
Fixes Help Menu editor settings so they properly point at modern documentation and forum URLs
Fixes handling of MenuBar so when inserting new items, ensures the menubar refreshes as would be expected
Adds remove function to menubar to remove a menu
Removes old commented console methods from menubar file
Adds checks for onMouseDown and onMouseUp for PopupMenu so items that are submenus aren't clickable like normal items
