data structures changed between openmm4 and openmm5.
added a check. not the gui should work for both versions.
fixing a typo in previous commit message:
was:
data structures changed between openmm4 and openmm5. added a check. not the gui should work for both versions.
should have been:
data structures changed between openmm4 and openmm5. added a check. NOW the gui should work for both versions.

:-)
Merge branch 'master' of github.com:js850/PyGMIN
Merge branch 'master' of github.com:js850/PyGMIN
implemented get_metric_tensor for normal mode calculation