Utility extend with two copy functions, copies elements from "input" LCCollectionVec to "output" kindof clone() method
compiler warning : comparison of signed and unsigned values: declare the counter "i" to be unsigned as its expected to be
adding fittrackvec and fithitvec collections from the daughter classes here. clear and get methods added. Both EUTelKalmanFilter and EUTelGBLFitter should be using these vectors.

+        // contains the fitted tracks, accessible through class methods
+        IMPL::LCCollectionVec * _LCIO_fittrackvec;
+
+        // contains the fitted hits, accessible through class methods
+        IMPL::LCCollectionVec * _LCIO_fithitvec;

_LCIO_fithitvec seems to be redundant.
the current plan is to have EUTelTrackImpl with a collection of EUTelTrackStateImpl as out definition of a track.
EUTelTrackStateImpl contains already track fit information as a track state at the scattering volume surface,
independently in the EUTelTrackImpl object there is a list of references to measured hit objects. which should be actually placed in EUTelTrackStateImpl objects.