Add bower support

This PR add bower support (as asked in #165).

You simply need to register your package on bower:

```console
$ bower register tagmanager git://github.com/max-favilli/tagmanager.git
```

There is only one problem: someone already registered an outdated fork of your project and you will have to ask to unregister it before here: https://github.com/bower/bower/issues/120