Merge pull request #80 from daritter/use_override_keyword

GBL/include/GFGbl.h

GBL/include/GblFitStatus.h

GBL/include/GblFitter.h

GBL/include/GblFitterInfo.h

core/include/MeasuredStateOnPlane.h

core/include/MeasurementOnPlane.h

fitters/include/DAF.h

fitters/include/KalmanFitStatus.h

fitters/include/KalmanFitter.h

fitters/include/KalmanFitterInfo.h

fitters/include/KalmanFitterRefTrack.h

fitters/include/ReferenceStateOnPlane.h

measurements/include/FullMeasurement.h

measurements/include/HMatrixU.h

measurements/include/HMatrixUV.h

measurements/include/HMatrixV.h

measurements/include/PlanarMeasurement.h

measurements/include/SpacepointMeasurement.h

measurements/include/WireMeasurement.h

measurements/include/WireMeasurementNew.h