Synchronized eye tracker data

[peabody124]

One limitation with the eye tracker software is that it relays the data out an
analog port. There is a non deterministic latency between when the frame
arrives and when it is out of the analog port. This is fine for real time control
(well not ideal but ok) but for post processing the data this isn't optimal.

We should deal with synchronization here how we do for all the other tasks.
The data should be streamed directly to disk (this is already implemented by
the record switch on the front panel). However, we also need to generate a
sync pulse to the 6608 and route it over the PXI_Trig# lines as well as create
database entries. This will allow zero latency synchronization.