Upgrading to Font-Awesome 4.0.3

Reference on Upgrading from 3.2.1
https://github.com/FortAwesome/Font-Awesome/wiki/Upgrading-from-3.2.1-to-4

Usage:
```
.x-tree-node-collapsed .tree-folder:before {
  @extend %pseudo-font;
  content:$fa-var-folder;
}
```

or:
```
.x-tree-node-collapsed .tree-folder:before {
  @include awesome-font; // same as %pseudo-font but just a mixin so usable within @media
  content:$fa-var-folder;
}
```

Please run `grunt build` which will fetch the new font-awesome via `grunt bower`.

```bash
cd revolution/_build/templates/default
npm install #if you need to
grunt build
```