fixed package.json using local grunt and bower

- Upgraded bower version to avoid `createTempDir ` issue https://github.com/bower/bower/pull/1403
- Using grunt locally as well inside package

Also, the [presentation can now indicate the usage](http://seattlejs.training.formidablelabs.com/starter-mac-linux.html#/4/3) of `$ npm run test` instead of `$ ./node_modules/.bin/grunt`
`npm` should already prepend those paths for these so that you *can* use locally installed ones on both Windows and Mac/Linux. This version will break on Windows...

Did you have something here that was not working?