Rename loaders to fit their locations

--HG--
branch : minor

src/modules/joystick/sdl/wrap_Joystick.cpp

@@ -151,7 +151,7 @@ namespace sdl
 		{ 0, 0 }
 	};
 
-	int luaopen_love_joystick(lua_State * L)
+	int luaopen_love_joystick_sdl(lua_State * L)
 	{
 		if(instance == 0)
 		{

src/modules/joystick/sdl/wrap_Joystick.h

@@ -45,7 +45,7 @@ namespace sdl
 	int w_isDown(lua_State * L);
 	int w_getHat(lua_State * L);
 	int w_close(lua_State * L);
-	extern "C" LOVE_EXPORT int luaopen_love_joystick(lua_State * L);
+	extern "C" LOVE_EXPORT int luaopen_love_joystick_sdl(lua_State * L);
 
 } // sdl
 } // joystick