[test] Move distance() tests to separate directory.
[test] Move from_wkt to main test directory and tweak #includes.
[test] Move set ops algorithms tests to separate directories.
[test] Move disjoint, relate and within tests to separate directories.
[test] Move IO tests from multi directory.
[test] Move set and relational operations tests to separate directories.
[test] Move relational operations tests from multi directory.
[test] Move set operations tests from multi directory.
[test] Move overlay tests from multi directory.
[test] Move the rest of the tests from multi directory and remove this directory.
Merge pull request #172 from awulkiew/feature/rearrange_tests

Feature/rearrange tests