How the smidr.flixel.FlxSmidr bridge manages the cursor while the pointer is over UI.
An enum abstract over Int, so it is just an Int at runtime (no allocation) while giving
named, type-safe values. Where a UICursorMode is expected the name can be written unqualified,
e.g. FlxSmidr.cursorMode = CURSOR_SYSTEM_OVER_UI; elsewhere use
UICursorMode.CURSOR_SYSTEM_OVER_UI. from/to Int keep it interchangeable with plain ints.
CURSOR_NONE— no cursor management (default)CURSOR_SYSTEM_OVER_UI— restore the system cursor while over UI, hide it again off UI