Update ErrorMatrixPropagator.cc
adding patch for ambiguity significance
patch for tau were the lifetime in negative
adding patch for numerical stability a sqrt calcualtion of tau 4-vector for derivatives
Merge branch 'master' of github.com:inugent/SimpleFits
fix value for the derivative so is works both for the rotated and unrotate uncertainty
Merge pull request #2 from inugent/numericalpatch

Numericalpatch