- pix-rotateprocedure
- in - PPIX
- in - ANGLE - radians, + is clockwise rotation.
- in - TYPE - one of: ROT-AM (area-mapping), ROT-SHEAR, ROT-SAMP (sampling).
- in - INCOLOR - fill-in from edges: select IN-WHITE or IN-BLACK
- in - WIDTH HEIGHT - use image w/h, or 0 for default.
- returns: ppix or #f if error.