Demo restore world state to original state after exiting.

[waynemwashuma]

System information.

Commit hash: 1b04130

Description.

Demos change world state thus affect other demos after switching to another demo.

Steps to reproduce.

This can be simulated by changing any resource/entity shared with other demos in one demo but not changed in others.

Test without switching demos but not switching to the demo changing world state.
Switch to the demo changing the resource then switch back and forth the other demos.

Expected behaviour.

Demos should get rid of the changes it made in the world before switching to another demo thus not affecting states of other demos.

Actual behaviour.

Demo leaves its changes affecting the states of other demos.

Cause(s).

The demos do not have a clean up strategy for restoring resources and entities to original state.