Add a settings flag to reenable MOSRotating objects absorbing particles when set toDelete

[traunts]

Requires merge of #480.

Followup to #480, relating to this TODO

The old behaviour of MOSRotating objects was to consume all atom collisions through MOSRotating::CollideAtPoint(), regardless of whether or not those collisions would be enough to destroy it (ie: set toDelete) via impulse/gib would limits.

New behaviour introduced in #480 changes this, where if an object is set toDelete == true then this method will break out and return false, allowing the atom to continue its travel and potentially impact other objects.
This vastly increases the damage done by explosions and other clustered damage sources, as a single attachable no longer shields all particles that interact with it in that frame.

Particles that are colliding and penetrating with a MOSR now omit said penetrations if the MOSR has already been flagged for deletion, often due to gibbing. This (sadly) fixes armor attachables acting as grenade fragment sponges, but makes explosives (and other particle spam devices) more efficient

The suggested resolution is to add a settings flag to optionally disable the new behaviour.

[Causeless]

I would suggested we make this a MOSRotating INI property, and not a settings flag, so it can be adjusted per-object. I'm assuming that's what you meant, but if this is a good-first-issue better to be explicit.