Improvements for InDetTrackTruthOriginTool

• Add a function getTruthOrigin, which determines the truth origin of a truth particle. getTrackOrigin call this function after checking the track TMP and fetching the linked truth particle.
• Add an exclusive origin label, which is useful in cases where the inclusive origin returned by getTrackOrigin contains too much information. The possible exclusive origins are given in the enum:

    enum ExclusiveOrigin {
      Pileup         = 0,
      Fake           = 1,
      Primary        = 2,
      FromB          = 3,
      FromBC         = 4,
      FromC          = 5,
      FromTau        = 6,
      OtherSecondary = 7
    };