SYNOPSIS:
    SPLINE_TURN i|x|y|z degrees

DESCRIPTION:
    FIXME FIXME FIXME
    Set up the control points of the spline. ix and iy range from 0-3
    giving a total of 16 control points.

SEE ALSO:
    splines, SPLINE_SCALE, SPLINE_TURN, SPLINE_MOVE
