added .travis.yml


Former-commit-id: 153ae67032b0dc091d20c7b1309fde2ae49e25c3
moved .travis.yml to root dir


Former-commit-id: ca745c7f6b996ec3f508683ae938b3bcb21c2bdb
updated .travis.yml


Former-commit-id: 363b03a65aed65814f71d6aee02f1fc9f44228ec