skip dying for patients that are in a room

The pull request implements the behaviour described in the Issue #163.

Problem:
Patients die while in treatment (eg operating theatre). The room is then uneditable, the surgeon B-side is locked and can't be picked up/fired etc.

The room is then unusable and can't be fixed in-game. Patients queue and die because they are not treated.

Solution:
If the patient is in a room while health drops to `0.0` dying is skipped. The next tick outside a room will catch up if the patient is not cured then.
People that are cured and should have died make little to no difference to gameplay.