Cleanup header and triggers.

[mholtrop]

The header currently carries the trigger information that is only useful for 2016 data and stores those bits as "int".
The 2019 trigger data is in TSData, which has an incorrectly translated struct which is no longer a bitwise struct and contains an "unsigned int NA" and "unsigned int intval". The "intval" should be in a union with the bitwise struct.

Plan:
Make the header independent of the data set.
Make a new class for the 2016 trigger data.
Cleanup and make useful the TSData and VTPData banks for 2019.
Add methods to the EventHeader to retrieve trigger information in a uniform manner.