Add support for TrueType fonts

* Keeps original font system in place
* Uses the same API as original font system:
   - You can render only one line at a time
   - You can only use one font and color for one gr_text* call
* Caches all rendered text, with a string cache limited to 400
  entries, then it trucates to 250, which results in memory
  usage hovering around 5-10MB

Change-Id: I36107b9dcd8d57bae4486fce8b8f64e49ef3d906
Signed-off-by: Vojtech Bocek <vbocek@gmail.com>