add a static data member that enforces bit limits on pt for data formats

@mulhearn @jimbrooke I wanted to enforce some maximum values on the hwPt for the l1t DataFormats. Since we are sharing the formats with Stage2, I used a static member of each class and modified the constructors and setHwPt to respect the bit limit on the DataFormats. 

The default value for the number of bits is 30, which I chose to make sure that the behavior of signed int values for HwPt should not change (i.e. these commits shouldn't break any Stage2 code, hopefully). 

The bit values are set in the python configurations for now, I assume they should get moved to CaloParams object eventually just like firmware version. Again, if they are not explicitly set they default to 30.

I did not push this change myself since it has the potential (hopefully small) of breaking Stage2 code, and I will be on vacation soon and won't be able to fix problems. It has been build-and-run tested on the Stage1 code and behaves as expected.