Codechange: Use override specifer for overriding member declarations

This is a C++11 feature that allows the compiler to check that a virtual
member declaration overrides a base-class member with the same signature.

Also src/blitter/32bpp_anim_sse4.hpp +38 is no longer erroneously marked
as virtual despite being a template.

src/game/game_config.hpp

@@ -42,7 +42,7 @@ public:
 	bool ResetInfo(bool force_exact_match);
 
 protected:
-	/* virtual */ ScriptInfo *FindInfo(const char *name, int version, bool force_exact_match);
+	ScriptInfo *FindInfo(const char *name, int version, bool force_exact_match) override;
 };
 
 #endif /* GAME_CONFIG_HPP */