boost.sort header conflicts with boost.range header

See https://svn.boost.org/trac10/ticket/11202 which seems to be abandoned.

In `boost/range/algorithm/sort.hpp` (https://github.com/boostorg/range/blob/develop/include/boost/range/algorithm/sort.hpp#L65) there's
```
} // namespace range
using range::sort;
} // namespace boost
```
which pollutes the `::boost` namespace with `sort`. But `::boost::sort` is a namespace used here: https://github.com/boostorg/sort/blob/develop/include/boost/sort/heap_sort/heap_sort.hpp#L25

This means I can't use both `boost::sort` and `boost::range::sort`.

This appears to violate https://svn.boost.org/trac10/wiki/Guidelines/MaintenanceGuidelines#Avoidtheinclusionofsymbolsattheboostorboost::detailnamespace