Add dependencies to package.json

I ran into the following issue while trying to get setup to work on the
jquery codebase.

    $ npm install
    ...
    > jquery@2.1.0-pre install /private/tmp/jquery
    > bower install

    sh: bower: command not found
    npm ERR! weird error 127
    npm ERR! not ok code 0

The fix is simply to add bower to devDependencies.

After running bower I ran into an issue needing grunt-cli.

The fix is simply to add grunt-cli to devDependencies.

With these dependencies defined we no longer need to
explicitly tell travis to install these dependencies.