Configure this project to be consumed by Bower

This PR adds a `bower.json` file to your project, allowing anyone using the Bower package manager to easily integrate the plugin into their application.

In addition to merging this code, you'll need to [register this package with Bower](http://bower.io/#registering-packages) by running `bower register jQuery-Tag-This https://github.com/dangribbin/jQuery-Tag-This`. Also, in order to use this you'll need to start tracking your releases with [semantic versioning](http://semver.org/), that way package managers like these don't get confused.