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>
diff --git a/gui/resources.hpp b/gui/resources.hpp
index 874836e..3cb5281 100644
--- a/gui/resources.hpp
+++ b/gui/resources.hpp
@@ -38,6 +38,14 @@
 class FontResource : public Resource
 {
 public:
+	enum Type
+	{
+		TYPE_TWRP,
+#ifndef TW_DISABLE_TTF
+		TYPE_TTF,
+#endif
+	};
+
 	FontResource(xml_node<>* node, ZipArchive* pZip);
 	virtual ~FontResource();
 
@@ -46,6 +54,7 @@
 
 protected:
 	void* mFont;
+	Type m_type;
 };
 
 class ImageResource : public Resource