Obsolete function object_add, sound_add

[RaniSputnik]

These scripts;

Resources/Management/map_objects
Resources/Management/map_sounds

Both use obsolete functions object_add and sound_add respectively. We should be able to modify these scripts to work without these functions as they are simply used to determine the latest id used by new sounds / objects. We could simply loop over a predefined range of ids? Not as foolproof but should still be functional.

[gmlscripts]

Unless I can come up with something smarter, I think adding an argument to set the limit of the scan is the best way to go, with a default limit if no argument is given.