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>

gui/input.cpp

@@ -139,7 +139,7 @@ GUIInput::GUIInput(xml_node<>* node)
 		attr = child->first_attribute("resource");
 		if (attr) {
 			mFont = PageManager::FindResource(attr->value());
-			gr_getFontDetails(mFont ? mFont->GetResource() : NULL, &mFontHeight, NULL);
+			mFontHeight = gr_getMaxFontHeight(mFont ? mFont->GetResource() : NULL);
 		}
 	}