[algorithms][disjoint] implement disjoint for the following combinations:
* multipoint / point
* multipoint / segment
* multipoint / box
* multipoint / multipoint
[test][algorithms][disjoint] add test cases with empty multipoints;
enable tests for the combinations:
* point / multipoint
* multipoint / multipoint
* multipoint / segment
* multipoint / box
[algorithms][disjoint] add alternate implementation for
disjoint(multipoint, multipoint) that uses BG's partition;
Merge branch 'develop' of https://github.com/boostorg/geometry into feature/disjoint-1.57
[algorithms][disjoint] rename struct multipoint_geometry to
multipoint_constant_size_geometry
[algorithms][disjoint] factor-out common functionality in disjoint_multirange_segment_or_box
and multipoint_constant_size_geometry; simplify implementation of disjoint_segment_areal;
[algorithms][disjoint] remove partition related code
[algorithms][disjoint] add missing include; replace for-loop by call
to check_iterator_range<...>::apply;
[iterators][closing_iterator] remove assignment operator (it is the
same as what the compiler would generate, so not need to provide it)
[iterators][ever_circling_iterator] remove assignment operator (it is
the same as what the compiler would generate, so no need to provide it)
[iterators][concate_iterator] remove templated assignment operator (it is not
really needed since the compiler constructed assignment operator and the
templated constructor, combined, do what this assignment operator does)
[iterators][segment_iterator] remove templated assignment operator from
range_segment_iterator class (it is not really needed since the compiler
constructed assignment operator and the templated constructor, combined,
do what this assignment operator does)
[iterators][flatten_iterator] re-write line in less than 80 characters;
remove templated assignment operator (it is not really needed since the assignment
operator defined and the templated constructor, combined, do what this assignment
operator does)
[algorithms][distance] fix bug in multipoint to areal geometry computation
[test][distance] add test cases for multipoint/polygon and
multipoint/multipolygon with points inside the polygon/multipolygon
[iterators][flatten_iterator] change statement layout to be nicer
Merge pull request #173 from mkaravel/fix/assignment_operators_for_iterators

Fix/assignment operators for iterators
Merge pull request #174 from mkaravel/fix/distance

Fix/distance
[doc] Add distance() fix (MPt/Poly, MPt/MPoly) to release notes for 1.58.
Merge branch 'develop' of https://github.com/boostorg/geometry into feature/disjoint-1.57