Start adding to the drift chamber code.   Setup a class structure
      similar to what podd uses for the VDCs.  Raw hit class renamed
      to THcRawDCHit.  Signal hits are how THcDCHit, modeled after
      podd hits.  Add THcDCWire, and classes for time to distance conversion.
      Time to distnace conversion doesn't do anything yet.

      Find some improved DC parameter files so that min and max TDC limits
      are good for the run we are using.

      THcDriftChamberPlane asks ThcDriftChamber for many parameters.

TClonesArray ConstructedAt method.

Raw hit class for drift chambers and skeleton drift chamber that prints
out drift chamber package hits.

Move Compare method from THcHodoscopeHit to ThcRawHit since it should
work for any derived class.

Get detector name -> ID mapping from the map file comments