better check on psm features

src/pappsomspp/psm/features/psmfeatures.cpp

src/pappsomspp/psm/peptideisotopespectrummatch.cpp

src/pappsomspp/psm/peptideisotopespectrummatch.h

...ppsomspp/widget/massspectrumwidget/massspectrumwidget.cpp

...pappsomspp/widget/massspectrumwidget/massspectrumwidget.h

tests/test_psm.cpp