Fixes building when using scons 3.0 which apparenlyt uses python3.
  Fixes broken building on travis

autogeneration of src/HallC_LinkDef.h - all using SCons

  Provides methods get NSA, NSB, and NPED for each crate

Added new class THcRawTdcHit.
RawShowerHit update.

The new class THcRawAdcHit is meant to represent the raw ADC hits. The
logic with dealing with ADCs has become quite complex now and it would
have to be multiplicated across all detectors that have ADC
channels. While this by itself is not such a big problem, fixing
possible bugs in multiple places is.

I also redesigned the THcRawShowerHit class to use the new
THcRawAdcHit. The redesign was due anyway, so I took the opportunity.

I also had to modify THcShowerArray and THcShowerPlane. They still
need some work to use the the new flash 250 data, but changes were
necessary anyway.

Minor fix 01.

Dummy spectrometer class.
Added a dummy spectrometer class to ease the construction of teststands for single detectors.

       This is to match the class name defined in those files
       Also add THcShowerHit to the Makefile

Access the energy of the golden track from THaGoldenTrack.

    Include THaTrack.h in THaGoldenTrack.h.
    Add GetEnergy method in THaGoldenTrack.h.
    Define variable name "e" for the energy of golden track in THaGoldenTrack.C.