Always up to date: We read the yaml from the font awesome repository. Just specify your version and you're read to go.
Optional on the frontend: We know on the frontend you might like to bundle your own font awesome icons, so you choose if you want us to load them from the CDN.
It should convert [fa icon='star' classes='some extra classes'] into <i class="fa fa-star some extra classes"></i>)
Any attributes other than icon or classes should be passed along as is e.g. [fa icon="star" classes="another" title="A star"] would be <i class="fa fa-star another" title="A star"></i>
It should be optional (a register_shortcode option in the yml probably enabled by default)