Add utilities for retreiving the contexts associated to an agent.
Fix the unit test code for the network config.
Enable to display the stack trace in the log.
Fixing the unit test code.
Simplification of the logger implementation.
Avoid NullPointerException in the ZeroMQ implementation.
Enforce the building of the LogRecord in the uncaught exception handler.
Add the thrown exception AgentKillException to the prototype of killAgent().
Remove unecessary code from Context implementation.
Delete the spaces when the space repository is destroyed (issue #43).
When destroying the inner context of an agent, this agent must be unregistered from the corresponding default space (issue #43).
Verify if an agent can be killed before starting the killing process (issue #43). An agent can be killed only if there is no more subagent in the inner context.