TODOS: -------- * Add --socket option if no HOME found (sessiond) * Use realloc() in ask_sessiond() (liblttngctl) * perror() --> PERROR() (everywhere in the code) * Use lockfree hashtable for tracing session list (session.h/.c) * Complete lttng ust 2.0 support (all features) (in progress David G. et Mathieu D. - 03/11/2011) * Add a command to "lttng" to consume data when the tracer is in flightrecorder mode