working on doc

docs/Doxyfile

docs/Makefile

docs/reference.rst

docs/smart-ranges.rst

src/polymesh/Mesh.hh

src/polymesh/attributes.hh

src/polymesh/detail/unique_array.hh

src/polymesh/detail/unique_ptr.hh

src/polymesh/fwd.hh

src/polymesh/low_level_api.hh

src/polymesh/ranges.hh