COMMAND NAME:	polarizations

TYPE:		Data selection

SYNTAX:		"polarizations RR LL RL LR"

DESCRIPTION:

Sets the polarization data selection parameter in the inputs.  Only
those polarizations specified will pass the filter-applying operations
of edit inputs, read, and plot.  Typing "polarizations" without
arguments removes any restrictions on allowed polarizations.  Specified
polarizations must be a subset of RR, RL, LR and LL.

This command is relevant only for Mk4 data, afile versions >=5.