Load fonts using FreeTypeFontLoader (AssetManager)

Essentially, `FreeTypeFontLoader` loads `BitmapFontGroups`, which are `HashMaps` that contain different `BitmapFonts` based on the same `FreeTypeFont`. In order to get a specific `BitmapFont` from assets, you must first get the `BitmapFontGroup` you want, then get the specific `BitmapFont` that you want.

Here is `generateFont()` from `LevelTitleScreen` as an example:

```
private BitmapFont generateFont() {
    BitmapFontGroup corbel = assets.get("corbelb.ttf");
    return corbel.get("title");
}
```

The method `makeCorbelParams()` in `LevelScreen` should be an adequate example of how to load fonts with the new loader.