qRegisterMetaType<std::vector<std::string>>("std::vector<std::string>");
connect(ui->preview1, SIGNAL(transition_names_updated(std::vector<std::string>)),
this, SLOT(set_transition_names(std::vector<std::string>)));
qRegisterMetaType<std::vector<std::string>>("std::vector<std::string>");
connect(ui->preview1, SIGNAL(transition_names_updated(std::vector<std::string>)),
this, SLOT(set_transition_names(std::vector<std::string>)));