make extension parsing in importSBML more explicit [no-ci]
make extension parsing in importSBML more explicit [no-ci]

FFroehlich/AMICI,AMICI-developer/AMICI,FFroehlich/AMICI,AMICI-developer/AMICI,AMICI-developer/AMICI,AMICI-developer/AMICI,FFroehlich/AMICI,FFroehlich/AMICI