message: add alternative version of hit search in tracklet constructor using same hitarea as neighbors finder, which does the 'correct' thing searching through all hits in the right area
diff: #include "AliHLTTPCCADef.h"
  #include "AliHLTTPCCATracklet.h"
  #include "AliHLTTPCCATrackletConstructor.h"
  +#include "AliHLTTPCCAHitArea.h"
  +#include "AliHLTTPCCAHit.h"
  #define kMaxRowGap 4
  @@ -273,11 +275,27 @@ MEM_CLASS_PRE2() GPUdi() void AliHLTTPCCATrackletConstructor::UpdateTracklet
  #ifndef HLTCA_GPU_TEXTURE_FETCH
  GPUglobalref() const ushort2 *hits = tracker.HitData(row);
  #endif //!HLTCA_GPU_TEXTURE_FETCH
  -
  float fY = tParam.GetY();
  float fZ = tParam.GetZ();
  int best = -1;
  + float ds = 1e6;
  + AliHLTTPCCAHitArea area;
  + area.Init(row, tracker.Data(), fY, fZ, 1.5, 1.5);
  + while (true)
  + {
  + AliHLTTPCCAHit hh;
  + int ih = area.GetNext(tracker, row, tracker.Data(), &hh);
  + if (ih < 0) break;
  + float dy = hh.Y() - fY;
  + float dz = hh.Z() - fZ;
  + float dds = HLTCA_Y_FACTOR * fabs(dy) + fabs(dz);
  + if ( dds < ds ) {
  + ds = dds;
  + best = ih;
  + }
  + }
  +
  { // search for the closest hit
  const int fIndYmin = row.Grid().GetBinBounded( fY - 1.f, fZ - 1.f );
  assert( fIndYmin >= 0 );
  @@ -285,7 +303,6 @@ MEM_CLASS_PRE2() GPUdi() void AliHLTTPCCATrackletConstructor::UpdateTracklet
  float ds = 1e6;
  unsigned int hitYfst[2], hitYlst[2];
  -
  {
  int nY = row.Grid().Ny();
  