THcSpacePoint
  1) added fSetStubFlag which is intialized
     to kFALSE in constructor and set to kTRUE
     when SetStub is called.
   2) added method GetSetStubFlag which
      returns fSetStubFlag.

THcDriftchamber
   1) In ProcessHits increased fHits reserve to 40
   2) In FindSpacePoints use fSpacePoints->Delete();
   3) In LeftRight ,only SetStub if the Stub is fit.

THcDC
   1) In LinkStubs
      a) only link stubs if number of total spacepoints <10
      b) only link stubs if both spacepoints have SetStubFlag true

THcDCHit.h
   1) In constructor initalize fLR to 0

THcDCTrack.cxx
   1) AddSpacePoint check if fnSP < 10

Modified THcSpacePoint.h to have public member that keeps track
   of the spacepoint ID number for each chamber.
   Used in THcDC::LinkStubs

Modified THcDC.cxx and h
1) Add tree variables sp1_id and sp2_id which are the integer
    ID in the spacepoints in each chamber used in the golden track.
     The ID refers to index in array of spacepoints created in
     THcDriftChamber.cxx

2) Modify LinkStub to fill sp1_id and sp2_id for each track

3) For golden track fill sp1_ID_best and sp2_ID_best

Add calls:
+  Double_t GetStubX() {return fStub[0];};
+  Double_t GetStubXP() {return fStub[2];};
+  Double_t GetStubY() {return fStub[1];};
+  Double_t GetStubYP() {return fStub[3];};

   {prefix}dc_fix_lr
        Historically, in the ENGINE, if a hit is used in multiple
        space points/stubs, the left/right assignment for that hit, which
        is later used in track fitting, is that assigned for the last stub
        encountered with that hit.  Properly, the left right assignment
        should be allowed to be different in different space points.  If
        this parameter is set to zero (e.g. in hcana.param), then the
        ENGINE behavior is used.  For new analyses, it should be set to one.
        (Which is the default)
   {prefix}dc_fix_propcorr
        When a hit gets put into a stub, the distance of the hit from the
        discriminator can then be estimated.  In the engine, a correction to
        the drift time (and thus drift distance) is applied.  However, if
        that hit ends up in another stub, the correction will get applied again,
        resulting in a over correction.  Setting this flag to 1 will give that
        hit a different corection for each stub that it is in.

These flags will default to the new "correct" way of handling hits if
the above parameters are not set in a parameter file.  Currently, both
flags are set to zero in hcana.param to replicate the ENGINE behavior.

To implement these changes, the propagation correction and L/R information
for each hit is saved in space point and track classes.  This information
is still saved in the hit class, but only used if in ENGINE compatibility
mode.

The THcDCTrack class now saves a list of space point pointers instead
of space point indices.

The AddSpacePoint method now also copies all the hit information into
the track object so that THcDC doesn't need to explicitely copy all
the hits.

The FindStub method, which fits a stub track to a space point is passed
the space point rather than a list of hits

  Compiles and doesn't crash.

  THcDriftChamber::SpacePoint -> THcSpacePoint
  That way space points can be put in a TClonesArray and be made known
  to THcDC when stub information is added.