[evlatests] Single dish vlbi

[Barry Clark]

When we were trying single dish vlbi, we were running it in a 'stealth'
subarray, which just controls the antenna, and does not inform the 
correlator or idcaf that the subarray exists.  Ken has suggested that
it would be easiest to extract calibration data from the archive record.
So I tried to see what would happen if we tried a 'normal' single dish
subarray.

Continuum worked OK.  I rather suspect that no data whatsoever was 
written for the single dish subarray, but I didn't look.

Spectral line did not work.  I suspect it was the correlator controler
that got unhappy, since idcaf said 'no visibility data received'.