Suspend simulation

In some situations a world author wants to set up the world in a “suspended” state, where the simulation isn’t running. In this state nothing grows or moves. This prevents the world being altered while it’s being worked on. Once the world is in a “ready” state the simulation can then be turned back on. This is even more of use when a world is made to be exported.
This should be accomplished by setting the property “suspended” on the world entity to the value “1”.