Testing data for the retargeting

[etrigger]

I tried to build the roboptim-retargeting project, however, it failed to find the model as claimed in the CMakeLists.txt under roboptim-retargeting/tests/CMakeLists.txt
# Look for the HRP4C model.
FIND_PATH(HRP4C_DIRECTORY
NAMES HRP4Cg2main.wrl HRP4Cg2.yaml HRP4Cmain.wrl HRP4C.yaml
DOC "HRP-4C directory (as expected by Choreonoid, i.e. containing YAML files)"
)
I found some sample data under roboptim-retargeting/share/roboptim/retargeting/data/(human-to-hrp4c.morphing.yaml+sample.body-motion.yaml), but I am not sure if they are the missing data defined in the CMakeLists.txt shown above.

[bchretien]

The build references some proprietary data that cannot be shared publicly (and that I don't have anyway). Until alternate test cases are available, I guess we could just make the tests optional.