Limit Travis tests to React Native releases with major packager changes (0.13, 0.15, 0.17)
Limit Travis tests to React Native releases with major packager changes (0.13, 0.15, 0.17)

Also, do not run tests with npm 2 anymore. The Babel 6 dependency tree is vast and makes the RN packager start up very slowly on Travis.

hammerandchisel/react-native-webpack-server,mjohnston/react-native-webpack-server