Classes under "rulesets" have been moved to "rules", and split up into
futher subdirectories matching their library. As a result we can now
better separate the python bindings, so that things that belongs to the
simulation are separeted from things that belongs to the ai.
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.