lilypond 2.13.42 released

We are happy to announce the release of LilyPond 2.13.42. This
release contains the usual number of bugfixes. However, a number
of critical issues still remain, so this release is intended for
developers only.

Please note that this is not the second beta test. Due to a number
of untested changes to our build process, we cannot be at all
confident about the quality of this release. 

Cheers,
- Graham