chore(.travis.yml): Only run 'unit' tests in macOS
chore(.travis.yml): Only run 'unit' tests in macOS

dreal/dreal4,soonho-tri/dreal4,dreal/dreal4,soonho-tri/dreal4,soonho-tri/dreal4,dreal/dreal4,dreal/dreal4,soonho-tri/dreal4