== MS_unwind_pm_90

 MS_UNWIND_PM_90 - Unwind an angle until it is between 0 and 360 degrees

 // Part of MSAT - The Matlab Seismic Anisotropy Toolkit //

 Utility function to find the equivelent angle between 0 and 360 degrees. 

 [angle] = unwind_pm_90(angle_in)

 Usage: 
     for a given value of angle_in return a value greater than 
     -90 and less than or equal to 900 by repetedly adding or subtracting
     180. Angle can be a scalar or a vector.
