First pass script to update run tables

[mcb64]

This also includes some changes to the epicsarchiver module:

• Don't round to the nearest second if the new useMS parameter is True.
• Get religion about having all datetimes in UTC. Moreover, convert to UTC using standard routines.

One important point to be discussed is that this script currently just grabs data from the archiver, and puts in the last value prior to the start of the run. If an archiver API exists to test if the PV was connected at this point, we should add a check here. If no such API exists, it would not be unreasonable to assume "old" values (for some definition of old) are no longer valid. (We might want to add these anyway... it's a point of discussion, as I said.)

[mcb64]

No, it checks if you were disconnected at the start of the run, and doesn't add data if you were.

I had sent mail to Murali... what I'm doing here is not terribly efficient, and he should be able to provide a single call to give me the second data point that I need instead of having me search for it. But putting in that call could be a future PR...