Add bower.json

[mulderp]

It would be great to have a basic bower json file to pull in JS dependencies, e.g.:

{
  "name" : "lib",
  "version": "0.1",
  "dependencies" : {
    "jquery" : "latest",
    "underscore" : "latest",
    "backbone" : "latest",
    "handlebars": "latest"
  },
  "install" : {
    "path" : "./assets/javascripts/libs"
  }
}

Would be a nice start for a Backbone sandbox.