[evlatests] Holography working, as expected

[Rick Perley]

    I checked the holography modes, looking for unexpected troubles.  To 
do this, I ran two raster scans across the antennas at L-band, within 
the mainbeam only, with oversampling of 9, and 0.416 sec dump time.  
This gross oversampling allows for careful inspection of what the 
antennas are actually doing. 

    All antennas -- both EVLA and VLA, appear to be rastering as 
desired.  Stopping points begin and end exactly as requested, and all 
antennas appear to be in perfect synchronism.