Enable by defining HITPIC in THcShowerArray.h

  GetData accepts a pedestal range and an integration range.
  Samples in the integration range are added after subtracting the
  average of the pedestal range from each sample.
  Method also provided to return dynamic pedestal

  A shower counter hit can now be multiple samples, with a different
  number of samples allowed for positive and negative tubes.
  GetData(signal) now returns the sum of all the samples.  This should
  still be compatible with fastbus ADCs as they are a single sample
  (which is already the integral.)

  Added as an optional sub detector THcShowerArray to the THcShower class
  Get hit data with GetData method instead of hit member variables
    so as to be compatible with FADC compatible hit list