This addresses the main issue with TObjPtr, namely that using it required pulling in the entire class hierarchy in basic headers like r_defs which polluted nearly every single source file in the project.
This was done to ensure it can be properly overridden in scripts without causing problems when called during engine shutdown for the type and symbol objects the VM needs to work and to have the scripted version always run first.
Since the scripted OnDestroy method never calls the native version - the native one is run after the scripted one - this can be simply skipped over during shutdown.
Needless to say, this is simply too volatile and would require constant active maintenance, not to mention a huge amount of work up front to get going.
It also hid a nasty problem with the Destroy method. Due to the way the garbage collector works, Destroy cannot be exposed to scripts as-is. It may be called from scripts but it may not be overridden from scripts because the garbage collector can call this function after all data needed for calling a scripted override has already been destroyed because if that data is also being collected there is no guarantee that proper order of destruction is observed. So for now Destroy is just a normal native method to scripted classes
They were immediately deleted when the associated thinker was destroyed. But this was too early because it missed the final tic of movement, resulting in a visible jump when a moving platform with a player on it came to a halt.
Changed it so that DelRef no longer destroys the interpolation itself. Instead the ::Interpolate method will check if the reference count is 0, and if so and there was no more movement, will then destroy the interpolation.
This ensures that it keeps running until it has interpolated all remaining bits of movement induced by the thinker.
Now moving up a lift is 100% smooth, even with movement interpolation on.
* FInterpolator depended on external references to prevent its content from getting GC'd.
* none of the pointers in the interpolation objects were declared to the GC.
The result of these issues was that changing anything about the life cycle of interpolation objects caused corrupted memory crashes when a level was changed.
