Rect points

Allows getting "the effective points" of graphic rectangles, round rectangles, and regular polygons.
This allows for some things that are difficult at present: setting the points of a freeform polygon to one of several regular polygon objects; moving an image around the points of a regular polygon, etc.
I think you need to delete fakepoints here too as MCU_round_rect I believe allocates a new array if the input array is nil.