Move robot initialization parts to sot-application

  Some initializations that used to be performed in this package were in fact
  application dependent. These initializations have been moved to the new
  package sot-application.
  - class solver has been removed,
  - features and tasks are not created anymore in AbstractHumanoidRobot class.
Add ZmpFromForces entity

  Compute zmp from force sensors in the feet.
Update the kine_romeo sample.

The solver has been moved in sot-application.