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.
We now register a an external mind with the ExternalMindsManager and
then let the manager make sure that there's an external mind connected.
When the external client is disconnected the manager will try to find a
new client to handle the mind.