remove unused deps, bumps travis min versions

Author: flovilmart

package.json

@@ -49,7 +49,6 @@
     "babel-core": "~6.24.1",
     "babel-eslint": "^7.2.3",
     "babel-loader": "~7.0.0",
-    "babel-plugin-remove-proptypes": "~1.0.0",
     "babel-plugin-transform-decorators-legacy": "^1.3.4",
     "babel-polyfill": "^6.23.0",
     "babel-preset-es2015": "^6.24.1",