Added bower.json file to support installation from bower

Hey! Here's the `bower.json` file, just like I promised :)

Pablo now shows up in the bower packages. But in order for bower to show the contents of the `bower.json` file, you need to have git tags for each Pablo version/release (using semver). This is not required, but it improves the metadata and allows users to define specific version dependencies in their projects.

You can now install Pablo with `bower install pablo` :)