Port code to sot-core-v4.2.0

@ostasse made a source release of dynamic-graph (v3.4.0) and sot-core (v4.2.0). In sot-core there are some modifications of the API. RobotUtils objects are now available through RobotUtilsShrPtr instead of plain pointers and ParameterServer are now available from sot-core. @ostasse i s waiting for the migration to be done in sot-talos-balance before pushing to the binary packages.