Remove popup widget and its usage in menu
Menubar: Revert option formatting changes, fix commons unit test by including the valid select callback
Menubar: Format CSS source file, change 'dashed' to 'solid' (not visible, now less irritating)
Menubar: Move tests around, to more appropriate files
Menubar: Improve focus handling, keep it on last focused item when tabbing away and back, with unit test
Menubar: Rename menuElement option to menus, makes it consistent with Menu's menus option
Menubar: Rename icons.menu to icons.dropdown