This library provides a wrapper around select Mercurial functionality. We aim for the wrapper to be friendlier to use than Mercurial itself (the libraries, that is, which are largely undocumented) and also to provide a stable API. To achieve this, we will implement only the functionality we need, and if you ask nicely we might also implement the functionality you need too.
Also, Mercurial is licensed under the GPLv2+ and we use it under the terms of the GPLv3. This project is licensed according to the AGPLv3+, so if you're looking for a cushion from the strict copyleft license, this library is not your answer.
I know it's a little weird to host a project about Mercurial in a Git repository, but BitBucket is not impressive, and basically I didn't think it was worth off-GitHub hosting just for this small library. Sorry!