More specifically take into account the new headers of
abstract-robot-dynamics.

This commit allows to change on-line the constraints applied on the
feet. On-line modification such as in Dimitar2007, allows to script
the constraints modification. This calls for a proper synchronization
of information better handled in a separate class FootHalfSize.

Those values work for HRP-2, but prevented regression tests
with sample-humanoid-robot.

Reinforce policy to not externalize internal types.
This will help contributors by allowing internal
changes without impacting users.

Wrong return value on EndPhase of the walking.
This commit compiles.