Basically does nothing. Probably the system should send some message,
but for geometrical test of the robot behavior this will generate too much
unwanted error messages.
A proper way would assume level of debug messages according to the context.
Here we keep it simple.

  Application dependent initialization have been moved to a new package called
  sot-application.

  Moreover, it makes debugging cumbersome.

The ros spinner is now multi-threaded. The interpreter and the ros-node
are NOT anymore started in the main thread (breaking ART).

  User should set his own gain after initialization.

  Three data files are generated to be read by entity Seqplay in sot-tool:
    - posture,
    - leaf ankle,
    - right ankle,
    - center of mass,
    - expected force in left foot,
    - expected force in right foot.

  - accelerations in "accelerometer" signal,
  - angular velocities in "gyrometer" signal.

  Head of master does not succeed in compiling. Stop at last version that
  makes the package compile.

  Do not hard code prefix of dependency, use pkg config.

  Since this commit, method push of class Solver takes a task and not anymore
  a task name as input.

  This class is not used in the file and FeaturePositionRelative should be
  prefered.

Minor change: inverse header inclusion order.

Pb and solution pointed out and provided by F. Keith.