message: Add covariance matrix modification in the improver
diff: @@ -378,13 +378,13 @@ void AliAnalysisTaskSEImproveITS::UserExec(Option_t*) {
  // update secondary vertex
  Double_t pos[3];
  + Double_t covpos[6];
  v12->GetXYZ(pos);
  -
  + v12->GetCovMatrix(covpos);
  decay->GetSecondaryVtx()->SetPosition(pos[0],pos[1],pos[2]);
  + decay->GetSecondaryVtx()->SetCovMatrix(covpos);
  decay->GetSecondaryVtx()->SetChi2perNDF(v12->GetChi2toNDF());
  - //!!!!TODO: covariance matrix
  -
  // update d0
  Double_t d0z0[2],covd0z0[3];
  Double_t d0[2],d0err[2];
  @@ -493,10 +493,12 @@ void AliAnalysisTaskSEImproveITS::UserExec(Option_t*) {
  // update secondary vertex
  Double_t pos[3];
  + Double_t covpos[6];
  v123->GetXYZ(pos);
  + v123->GetCovMatrix(covpos);
  decay->GetSecondaryVtx()->SetPosition(pos[0],pos[1],pos[2]);
  + decay->GetSecondaryVtx()->SetCovMatrix(covpos);
  decay->GetSecondaryVtx()->SetChi2perNDF(v123->GetChi2toNDF());
  - //TODO: covariance matrix
  // update d0 for all progs
  Double_t d0z0[2],covd0z0[3];
  