Font awesome

I couldn't figure out how to detect if font-awesome was available client-side. Being the file loaded from a CDN, it's not yet present when the "useFontAwesome" helper is registered. Setting up a callback on some document listener didn't seem like a very good idea.

So I moved the decision server side. If the package font-awesome is installed, it'll use a different template, i.e. lib/reactive_table_fa.html (and lib/reactive_table_fa.css ).

It may not be the best approach though. :-)