Silenced some warnings.

include/common/eigen.h

include/common/point.hpp

include/libgmshdg/gmsh_io.h

include/libgmshdg/physical_element.h

include/timecounter.h

src/libgmshdg/gmsh_io.cpp

src/libgmshdg/timecounter.cpp

src/maxwell/maxwell_cpu.cpp

src/maxwell/maxwell_postpro.cpp

src/maxwell/maxwell_solver.cpp