In PreviousEventInfo, change from UnixTimeUTC to timestamp

To do this change, the following files need to changes:

* `utils/PreviousEventInfo.java`
* `container/PreviousEventInfoContainer.java`
* `datacorrection/PatchJumpRemoval.java`
* `utils/SamplePedestalEvent.java` (currently in branch SamplePedestalEvent but PR is coming shortly)

This changes should be done once SamplePedestalEvent is in to not create more confusion then necessary.
