Add lua_tofixed() and luaL_optfixed()

src/lua_script.h

@@ -34,7 +34,9 @@ extern "C" {
 // fixed_t casting
 // TODO add some distinction between fixed numbers and integer numbers
 // for at least the purpose of printing and maybe math.
+#define lua_tofixed(L, i) lua_tointeger(L, i)
 #define luaL_checkfixed(L, i) luaL_checkinteger(L, i)
+#define luaL_optfixed(L, i, d) luaL_optinteger(L, i, d)
 #define lua_pushfixed(L, f) lua_pushinteger(L, f)
 
 // angle_t casting