additional mouse_enter and mouse_exit functions?

[ben-wes]

the mouse_move(x, y) callback can be used to create hover feedback in pdlua GUI objects.

unfortunately, this has one major restriction though: the position is only reported on changes inside the object box and these changes are not necessarily reporting continuous coordinates. so there's no way to reliably determine whether the mouse has left the object area (or "crossed a border").

one option to deal with this might be additional functions. i learnt that @timothyschoen had these implemented some time ago and then removed them again since they seemed slightly hacky for vanilla. maybe they could be reconsidered though since they would allow for some additional interaction patterns.

one question in this context is whether mouse_enter and mouse_exit could also be achieved easily with purr data?