Add new POV tab for selecting which column has the tStamp, the time scale, etc.

1) So the user gets to PICK the tStamp column, instead of requiring it to be in the first column. 
2) Alternatively, they could  pick a  sequence column.
3) They could pick a typical time interval...  sec/min/hour/day
4) we could test if the data is OK before proceeding, perhaps? 
