0.6.1.1  Improve Semigroup instances.
0.6.1.0  Add safe versions of find... functions.

0.6.0.0  Support ghc 8.4, desupport ghc 7.x.

0.5.3.1  Remove HPC flag.
0.5.3.0  Add lookupLT... functions.

0.5.2.0  Bugfix: exported Prelude functions instead of correct ones.

0.5.1.1  Improve performance of findLast.

0.5.1.0  Major performance improvements.

0.5.0.1  Improve performance of combine.
	 Fix wrong doc comments.

0.5.0.0  Change return type of containing, ... to a map.
         Add splitAt, splitIntersecting, flatten... functions.
         Minor performance tweaks.

0.4.1.1  Fix bug in benchmark.

0.4.1.0  Add IntervalSet.
         Minor performance tweaks.
         Documentation updates.
         Moved to GitHub.

0.4.0.1  Documentation update. Wrong portability info fixed.

0.4.0.0  Major update adding support for user-defined key intervals.

0.3.0.3  Updated benchmark to use Criterion 1.0. Tested with ghc 7.8.3.

0.3.0.2  Dropped upper constraint on criterion. Tested with ghc 7.6.3.
         Migrated repo to Darcs Hub.

0.3.0.1  Bugfixes: Lazy was too strict, Strict too lazy.

0.3.0.0  Split into Lazy and Strict modules, following containers.