Documentation on hanning

Task: hanning
Purpose: Hanning smoothing
Categories: map combination

 Hanning does a hanning smooth on the velocity axis of miriad
 datasets. It figures out which axis this is from the header. If not
 given in the header it assumes that it is the z-axis.
 The width of the hanning smooth is determined by the keyword width.
 If input data is masked, it is set to zero before smoothing is done.

Key: in
	Standard in keyword. Use `help in' for more information.

Key: region
	Standard region keyword. Use `help region' for more information.
  NB the mask(file) option is not applied, set the mask of the input
  file.

Key: out
	Standard out keyword. Use `help out' for more information.

Key: width
 The number of channels of the hanning smooth. Must be an odd number.
 Default value is 3.