TODO

   1 - port changes from recent versions of lttng kernel
   2 - update to trace format 2.5
   3 - have per-cpu channels
   4 - make a trace testing script (that can assert whether a trace contains certain events)
   5 - make web site
   6 - use signal safe snprintf
   7 - fix header/lib priority problem at compilation
   8 - fix FIXME's in the code
   9 - make cli interface for flight recorder
  10 - add \n at end of messages in communication protocol
  11 - save_registers: save them only when the marker is active (complicated because we need to know their value at the address that is put in struct marker)
  12 - make streaming work
  13 - ustd should work as a pool of threads