Documentation on uvaflag

Task: uvaflag
Purpose: Use flags in one uv database to set flags in another
Categories: calibration

        UVAFLAG is a MIRIAD task which flags correlations in one 
        database when they are flagged in a template data base.
        Data bases must be identical except for the values of the
        correlations and the initial flag mask. 

Key: tvis
        The template input visibility file. No default.

Key: vis
        The input visibility file to be flagged. No default.