Revert "Topic/extra frames"

CMakeLists.txt

src/algorithm/extra-frames.hpp

src/multibody/model.hpp

src/multibody/model.hxx

src/multibody/parser/urdf.hxx

src/python/algorithms.hpp

src/python/data.hpp

src/python/frame.hpp

src/python/model.hpp

src/python/python.cpp

unittest/CMakeLists.txt

unittest/extra-frames.cpp