== MS_unwind_0_180

  UNWIND_0_180 - Unwind an angle until it is between 0_180 degrees

  [angle] = unwind_0_180(angle_in)

  This (obviously) assumes a 180 degree periodicity. Angle can be a scalar
  or a vector. 

  Created by James Wookey on 2007-05-08.

