Handle the activities for the Xcraft server. An activity begins with a command and accordingly to some conditions, the command is push in the waiting or in the running list.
The activity manager looks like a trivial scheduler.
A command (new activity) is executed only if:
- The same command with the same orc is not already executing.
- The activity is parallel or no other exclusive activity is already executing.
There are only two public (implemented) methods.