more range ops

Readme.md

src/polymesh/Mesh.hh

src/polymesh/algorithms/operations.hh

src/polymesh/attribute_base.hh

src/polymesh/attributes.hh

src/polymesh/detail/random.hh

src/polymesh/impl/impl_attributes.hh

src/polymesh/impl/impl_mesh.hh

src/polymesh/impl/impl_ranges.hh

src/polymesh/ranges.hh