SDL/Texture: made info struct take a texture ptr directly

Will allow me to construct one directly from a pointer if I don't have a wrapper object.

src/sdl/texture.cpp

@@ -100,7 +100,7 @@ void texture::destroy_texture()
 	}
 }
 
-texture::info::info(const texture& t)
+texture::info::info(SDL_Texture* t)
 	: format(0)
 	, access(0)
 	, w(0)

src/sdl/texture.hpp

@@ -43,7 +43,7 @@ public:
 	/** Small wrapper that queries metadata about the provided texture. */
 	struct info
 	{
-		explicit info(const texture& t);
+		explicit info(SDL_Texture* t);
 
 		Uint32 format;
 		int access;