Cleaned up warnings for gcc build

src/libqhullcpp/Coordinates.h

src/libqhullcpp/PointCoordinates.h

src/libqhullcpp/Qhull.cpp

src/libqhullcpp/QhullFacet.h

src/libqhullcpp/QhullFacetSet.cpp

src/libqhullcpp/QhullFacetSet.h

src/libqhullcpp/QhullHyperplane.cpp

src/libqhullcpp/QhullHyperplane.h

src/libqhullcpp/QhullIterator.h

src/libqhullcpp/QhullPoint.h

src/libqhullcpp/QhullPointSet.cpp

src/libqhullcpp/QhullPointSet.h

src/libqhullcpp/QhullPoints.h

src/libqhullcpp/QhullQh.h

src/libqhullcpp/QhullRidge.h

src/libqhullcpp/QhullSet.h

src/libqhullcpp/QhullStat.h

src/libqhullcpp/QhullVertex.h

src/libqhullcpp/QhullVertexSet.cpp

src/libqhullcpp/QhullVertexSet.h