Update to comply with Eslint v2
Update to comply with Eslint v2

Some rule have been deprecated, and generates warnings when linting with eslint v2+

`keyword-spacing` replaces: 
- http://eslint.org/docs/rules/space-before-keywords
- http://eslint.org/docs/rules/space-after-keywords
- http://eslint.org/docs/rules/space-return-throw-case

`no-labels` replaces http://eslint.org/docs/rules/no-empty-label
senecajs/eslint-config-seneca