[distance] fix unused variable warnings produced by clang++ with -Wextra and warnings by VS (reported by Adam)
Merge branch 'develop' of https://github.com/boostorg/geometry into feature/distance-for-merge
Merge pull request #27 from mkaravel/feature/distance-for-merge

[distance] fix unused variable warnings
[centroid] removed redundant distance include causing circular reference
for unit test "geometries/adapted"