gui: fix font scaling for zip themes

All fonts were extracted to /tmp/extract.bin which was deleted after
the initial load, so reloading for scaling failed.

- extract fonts to /tmp with original name and don't delete them
- minor code cleanup

Change-Id: If8a0f657a7ef4c418fd5cc8550a24de44a38f303
diff --git a/gui/resources.hpp b/gui/resources.hpp
index 4548c10..528fecc 100644
--- a/gui/resources.hpp
+++ b/gui/resources.hpp
@@ -29,21 +29,13 @@
 
 protected:
 	static int ExtractResource(ZipArchive* pZip, std::string folderName, std::string fileName, std::string fileExtn, std::string destFile);
-	static void LoadImage(ZipArchive* pZip, std::string file, gr_surface* source);
+	static void LoadImage(ZipArchive* pZip, std::string file, gr_surface* surface);
 	static void CheckAndScaleImage(gr_surface source, gr_surface* destination, int retain_aspect);
 };
 
 class FontResource : public Resource
 {
 public:
-	enum Type
-	{
-		TYPE_TWRP,
-#ifndef TW_DISABLE_TTF
-		TYPE_TTF,
-#endif
-	};
-
 	FontResource(xml_node<>* node, ZipArchive* pZip);
 	virtual ~FontResource();
 
@@ -54,7 +46,6 @@
 
 protected:
 	void* mFont;
-	Type m_type;
 
 private:
 	void LoadFont(xml_node<>* node, ZipArchive* pZip);