icub-models used in the robotology-superbuild

[traversaro]

Since robotology-superbuild PR robotology/robotology-superbuild#91 has been merged, now the icub-models repository is installed as part of the superbuild.

The icub-models repository contains URDF model files for the iCub robot that are automatically generated from the CREO CAD model of the iCub (and from other information sources for legacy model).
The models provided by this repo are automatically updated from the https://github.com/robotology/icub-model-generator repo,

The models provided in this repo supersede the models that used to be distributed in the https://github.com/robotology/yarp-wholebodyinterface , that will be removed in the next future. If you have any trouble or problem related to the new models, please open an issue in icub-models repo, thanks: https://github.com/robotology/icub-models/issues/new .

While some of the models contained in icub-models can be simulated in Gazebo, unfortunately icub-models is not a drop in replacement for the icub-gazebo repository, as the models in icub-models do not contain the eyes and the hands of iCub, that instead have been added in the past to the icub-gazebo repository. Check the issues robotology/icub-models-generator#37 and robotology/icub-models-generator#29 if you want to help adding the hands and eyes generation to the models contained in icub-models.
icub-models and icub-gazebo can be installed side-by-side without any problem, as done in the CORE profile of the robotology-superbuild.

cc @serena-ivaldi @InriaBrice