CREROT ( posn, axis, angle, transf, ifail )
===========================================

  Create a rotation transformation.

Receives:
  KI_vec_position           posn           --- position on axis
  KI_vec_axis               axis           --- axis direction
  KI_dbl_angle             *angle          --- rotation angle (radians)

Returns:
  KI_tag_transform         *transf         --- rotation transformation
  KI_cod_error             *ifail          --- failure code

Specific errors:
  KI_rot_angle_eq_0         zero angle rotation asked for

Description:
  Calculates a transformation matrix that, when applied to an entity,
  rotates it about the axis which passes through the given position. The
  angle of rotation (in radians) must not be within the resolution angle
  of zero. A 'right-hand screw rule' is assumed when calculating
  rotational direction with respect to axis direction.