qtgui: catch exceptions in QtOpenc2e::newNorn
qtgui: catch exceptions in QtOpenc2e::newNorn

bdonlan/openc2e,crystalline/openc2e,bdonlan/openc2e,bdonlan/openc2e,ccdevnet/openc2e,ccdevnet/openc2e,crystalline/openc2e,crystalline/openc2e,ccdevnet/openc2e,bdonlan/openc2e,crystalline/openc2e,ccdevnet/openc2e,ccdevnet/openc2e,crystalline/openc2e,ccdevnet/openc2e