TODOS:
--------

* Add --socket option if no HOME found (sessiond)
* Use realloc() in ask_sessiond() (liblttngctl)
* perror() --> PERROR() (everywhere in the code)
* Add a command to "lttng" to consume data when the tracer is in flightrecorder mode
* Fix error handling for UST support when enabling events on all applications.
* Support for UST remaining domains (PID, EXEC_NAME, FOLLOW_CHILDREN).
* Snapshot support.
* UDP support for network streaming.
* Optimize network streaming for throttle support.
