Modify THcShower, THcShowerPlane and THcShowerArray classes

Main purposes:
1) Add the possibility of multiple ADC hits per channel and
   select best ADC by a time window.
2) Change ProcessHits method in ShowerPlane and ShowerArray to only
    fill "raw" TClonesArrays.
3) Add CoarseProcessHits method to ShowerPlane and ShowerArray
    to fill the "good" data arrays from call in THcShower:CoarseProcess
4) Moved code to fill Track object with energy from FineProcess
   to CoarseProcess so that the Track->Get(Energy) can be used by other
    detectors in their FineProcess.
5) FineProcess loops over Track object add gets Track energy
6) Add AdcErrorFlag TClonesArray to be filled to check for
   problems with FADC




THcShower.h
1) Add methods GetADCMode(),GetAdcTimeWindowMin(),GetAdcTimeWindowMax()
    so that the ShowerPlane can access these parameters
2) Add parameters ADCMode,fAdcTimeWindowMin,fAdcTimeWindowMax
3) Add variables
   fNclustTrack : NUmber of cluster that matches best track
   fXclustTrack : X pos of cluster that matches best track
   fXTrack      : X pos of best track that matches cluster
   fEtrack  : Cluster energy associated with best track
   fEtrackNorm  : Cluster energy/Track momentum associated with best track
THcShower.cxx
1) Add calls to THcShowerPlane and THcShowerArray CoarseProcessHits
    in CoarseProcess
2) Moved filling of Energy in Track object to CoarseProcess
3) In FineProcess get the "best" Track object and match
   Track energy and trajectory to cluster.

THcShowerArray.h and cxx
1)add parameters fADCMode, fAdcTimeWindowMin and fAdcTimeWindowMax
2) Add method CoarseProcessHits
3) In ProcessHits fill fPosThresh and fNegThresh with a fix
    value of 250 integrated channels above pedestal.
     Need to make this a parameter.

THcShowerPlane.h and cxx
1)Gets fADCMode, fAdcTimeWindowMin and fAdcTimeWindowMax from THcShower
2) Add method CoarseProcessHits
3) In ProcessHits fill fPosThresh and fNegThresh with a fix
    value of 250 integrated channels above pedestal.
     Need to make this a parameter.