Adding trigger requirement for data, and other things.

Hi,

here are a couple of changes I'm proposing :
- Completely migrate event/sampleName/sampleType to global variables ;
- Remove the "CRx" names denomination, this was proposed by Caroline because the numbers are from historical reasons and we should stick as much as we can to explicit names... ;
- Added missing trigger requirements for data in channel definitions ;
- Added temp fix for the buggy eta cut on muons ;

Cheers,

Alex