Fix for iterators not being cleared after a GMX

[mikecnr]

The code from OnScriptInit now runs after a 0ms timer is called, to ensure the gamemode is reloaded after a GMX before clearing and re-processing the default iterators (e.g. Player, Vehicle etc.) as Iter_Clear doesn't seem to work under OnScriptInit after a GMX. Exact cause unknown. Probably related to the fact that GMX is crap and should be avoided!

[Y-Less]

OK, my only concern with this is what happens if the iterators are used in OnGameModeInit - like CreateVehicle etc. They'll be added then instantly destroyed. There are several options:

1. Clear them right at the end of OnGameModeExit instead.

2. Add a check to any hooked function that would call Iter_Add - OnPlayerConnect, CreateVehicle, etc, and if the init code hasn't run yet do it there first. Of course that also relies on that check variable somehow being correctly reset.

3. Figure out why Iter_Clear doesn't seem to work, especially since the timer is called so its not even a case of the callback not being called.

4. Don't use Iter_Clear there, just replace it with something else entirely like inline code.