Updated Cherenkov detector code
We have added a new parameter hcer_tot_pmts = 2 in hcana.param file.
It is equal to total number of PMTs in Cherenkov detector. With this
update, the THcCherenkov coarse process is complete. We have Raw adc,
pedestal subtracted adc, number of photo electrons and hits histograms
in the output root file for gas Cherenkov detector.
Fix title of xp in global variables list
Remove some old commented out code.
ThcCherenkov class.
Class for an Cherenkov detector consisting of two PMT's.
Fourth pull request. January 30 2014.
No need to cahnge the Map file.
New parameter hcer_tot_pmts = 2 is added to the hcana.param file
This code is for the coarse process of THcCherenkov class.
Names of all the variables are in lower case.

Variable Name   Description
phototubes      Nuber of Cherenkov photo tubes
adc             Raw ADC values
adc_p           Pedestal Subtracted ADC values
npe             Number of Photo electrons
npesum          Sum of Number of Photo electrons
ncherhit        Number of Hits(Cherenkov)
Merge remote-tracking branch 'upstream/develop' into develop

Conflicts:
	examples/PARAM/hcana.param