[evlatests] More on 2 subarrays / updates to idcaf

[Walter Brisken]

I've just committed some changes (that hopefully are also fixes) to idcaf. 
The older version is still running.  I think it would be worth testing 
this version with the 2-subarray test that Vivek ran last week.  I will 
try to deploy the updated idcaf at the next convenient test slot.


There are three changes since yesterday:

1. Activate new correlator document mode up to one integration earlier -- 
should fix one type of possible first integration problem.

2. If a new VlaCorrelatorMode document has a start time not on a 10-second 
IAT boundary, flag the integration during which the new document takes 
effect.  I think this is the most common cause of the "first integration" 
problems that folks have reported and it is clear that it is common that 
the first VlaCorrMode document of a file often starts with a start time 
not on a 10sec boundary.  A tolerance of 0.05 seconds is used.

3. If multiple documents of the same type/subarray have same start time, 
take the most recent one.  I would still feel more comfortable if idcaf 
didn't have to choose among conflicting documents!

-Walter