olorFast() for faster 24 bit color, about center

     b.  Rotation of an image of arbitrary bit depth, using
         either 2 or 3 shears.  These rotations can be done
         about an arbitrary point, and they can be either
         from source to dest or in-place; e.g.
         - pixRotateShear()
         - pixRotateShearIP()

     c.  Rotation by sampling.  This can be used on images of arbitrary
         depth, and done about an arbitrary point.  Colormaps are retained.

   The area mapping rotations