Fix some NPCs that create entities crashing when at the entity limit
Sandbox tool & constraint library improvements when at entity limit
Added filter_activator_context and filter_activator_model
Added new inputs/outputs to func_tracktrain
New inputs:
* SetMaxSpeed
* MoveToPathNode
* TeleportToPathNode
* LockOrientation
* UnlockOrientation
Outputs:
* OnArrivedAtDestinationNode