Dc calib fix (#421)

* Added functionality to loop over Max number of entries, if user enters entries exceeding this maximum :: Add calorimeter etot_norm cut for beackground cleanup

* DC Calib: added option to only perform ONLY EL-CLEAN trigger cut, which reduces the background events in the chambers

* added the requirement for each event to a ONLY 1 hit, by requiring ndata==1. This way, background produced from multiple hits can be reduced.

* 1). Set 'hdrift1stbin' parameter by +1 ns offset, to improve the drift distances. 2). Added variable 't_zero_final' which includes the tdc offsets (from HMS ONLY), as opposed to only including the tzero value. This is used in the LookUpTable method() 3). Remove 0.5 ns offset from the min/max time, which puts integer drift time values at the edge of a given bin 4). Reduced total number of bins in which the drift time integration is done from 274 ns to 189 ns, since it was determined (from a conversation with Mark Jones), that drift times beyond this value had no contribution to the drift distance.