Simplify the agent mechanism
Currently, the set of agents e.g. for CL is stored globally as an int array
in COOL and accessed through cl_{get,set}_agents
from the CoolUtils
. I would argue that we should change it to just the number of agents. This would lose the feature of having agents 1,7, and 12 without having the agent numbers in between for the gain of simplicity and making the code less error-prone.