Improve handling of errors in lua functions and speed up calls. (#1427)

src/Screen.cpp

@@ -360,8 +360,7 @@ bool Screen::PassInputToLua(const InputEventPlus& input)
 	{
 		callback->second.PushSelf(L);
 		lua_pushvalue(L, -2);
-		RString error= "Error running input callback: ";
-		LuaHelpers::RunScriptOnStack(L, error, 1, 1, true);
+		LuaHelpers::RunScriptOnStack(L, 1, 1);
 		handled= lua_toboolean(L, -1);
 		lua_pop(L, 1);
 	}