Feature/deadlock detection

[maarten-ic]

Add a deadlock detection mechanism to MUSCLE3.

New functionality:

• Instance sends a message to the manager when it is waiting for longer than muscle_deadlock_receive_timeout seconds (configurable in muscle settings)
• The manager reports deadlocks (a cycle of instances that are all waiting on each other) and shuts down the simulation

TODO

• [x] Implement Instance logic in C++ as well
• [x] Add integration tests
• [x] Add documentation