- Moves Graphics::loadFont to Graphics::NewFont::loadFont

- adds code for caching of fonts (just for Graphics::NewFont)
- implements cache using in the modern theme for custom fonts
- adds cache file for current normal font in the theme zip file

svn-id: r21952

gui/theme.h

@@ -364,6 +364,7 @@ private:
 	void setupFonts();
 	void deleteFonts();
 	const Graphics::Font *loadFont(const char *filename);
+	Common::String genCacheFilename(const char *filename);
 	const Graphics::Font *_fonts[kFontStyleMax];
 
 public: