Add set up instructions to README

Something like:

> * Run `bower install` and `npm install` to install the dependencies.
* Run `gulp test`to run the tests locally.
* Run `gulp` to build, so that you can view the results in a browser.

> For the example dashboard using the [Twitter Bootstrap](http://getbootstrap.com) grid for layout,  you'll need to run `bower install` from the `examples/bootstrap` directory.