log: test corectness when used in if statements.

Change-Id: I135902c13a021070c8d595ebb623a7c2e4750f2a
Reviewed-on: http://gerrit.aldebaran.lan:8080/12990
Reviewed-by: cgestes <gestes@aldebaran-robotics.com>
Reviewed-by: mnottale <mnottale@aldebaran-robotics.com>
Tested-by: mnottale <mnottale@aldebaran-robotics.com>
Add documentation for qilinguist

Change-Id: I07afa638fc1d7efe157e74cad42f8c383e1bf6ae
Reviewed-on: http://gerrit.aldebaran.lan:8080/12833
Reviewed-by: llec <llec@aldebaran-robotics.com>
Reviewed-by: jsuchard <jsuchard@aldebaran-robotics.com>
Tested-by: hcuche <hcuche@aldebaran-robotics.com>