Refactoring: Intdocued fix_agents function.

At each step we first check for possible malfunctions.
THen we apply them and do all the agent steps
At the end we look at what agents should be fixed. This lead so to:

Current malfunction value says how many step calls are necessary till agent can move again

e.g. malfunction = 2, we have to call step() twice untill the agent can move again.