use boost::locale instead of gettext

Change-Id: I362d48ccdf72c4fd2e6996415432ab0c0908f9fb
Reviewed-on: http://gerrit.aldebaran.lan:8080/18320
Tested-by: gerrit
Reviewed-by: hcuche <hcuche@aldebaran-robotics.com>
log: fix extra padding in timestamps

Change-Id: I665d4ab0d1401392efb9c71582d5d8d648bb5d49
Reviewed-on: http://gerrit.aldebaran.lan:8080/19166
Reviewed-by: vpaleologue <vpaleologue@aldebaran-robotics.com>
Reviewed-by: cgestes <gestes@aldebaran-robotics.com>
Tested-by: llec <llec@aldebaran-robotics.com>