forked from boostorg/core
* Work in progress, some tests fail * adding tests * missing header * moved close_to to detail, added constness, replaced predicates from <functional> with custom ones, new code does not rely on partial template specialization * renamed predicates and removed close_to predicate * removing now superfluous headers * unpatching the fix to put in a separate PR * move predicate to first argument * call op and anti_op as normal methods