This is defined by the naming of the property.
Properties that starts with "__" are private. Only visible to the
simulation and admins.
Properties that starts with "_" are protected. Like private but also
visible to the owning entity.
All other are public.
Entities that are "planted" on bodies of water are floating.
This does away with the "floating" mode.
To mark that entities should by default be floating when placed in
water the boolean property "floats" has been added.
