Updated to build without warnings in the wake of GHC 7.10.
Use (and re-export) the new overloaded null and length from Prelude on GHC 7.10+
Modified mkeep, mdrop and mlca to parameterize them by monoid homomorphisms. This permits cheaper summaries to be calculated over the dropped path, when only a portion of the information in the path is required.
Fixed a bug in path reconstruction
Improved documentation to also note that this package also provides an improvement in the online version of the level ancestor problem.