[evlatests] modcomp-free: fast switching, flags, quack.

[rperley at nrao.edu]

 Vivek noted:

> 2. The online flags are cutting off a bit of good data, 0 or
>     1 integrations at the start of each scan, and a bit more,
>     usually 2 or 3 but occasionally upto 5 integrations at the
>     end of each scan. I believe from previous emails that this
>     tolerance is band-dependent, and might bother someone doing
>     very short scans at Q band, is it worth testing?

The time it takes for the antennas to settle down at the beginning is
certainly band dependent -- it is much worse for L and C bands (and
probably P-band) than any other.

I've never noted any band dependence for the end-of-scan problems, which
only affect EVLA antennas.  We often lose the final second of data, and
occasionally a full 10 seconds (exactly).  So there are still a few issues
here.