Now set up the model's activation. swarmContext indicates where
we're being started in - typically, this model is run as a
subswarm of an observer swarm.
This is a ghost agent which simply transfers the 'act' message to
the first agent in the list agentList and rotate it
this trick is necessary to send the act message agentNumber times; so
the observer can dispaly the price of each acting step.
LocallyImitatingAgent inherits from BasicSumAgent and operates in an imitative way,
following other agents actions(last operating agents or "local" imitation).