* Documentation/user/music-glossary.tely: add @omf tags

* Documentation/user/music-glossary.tely: add @omf tags

* Documentation/user/lilypond.tely: add @omf tags

* scm/generate-documentation.scm (string-append): add @omf tags.

* input/regression/multi-measure-rest.ly (texidoc): add doco

* GNUmakefile.in (web-doc-install): add web-doc-install target

* lily/scm-hash.cc (remove): prevent underflow of elt_count_. This
fixes crashes while dumping MIDI.

* ly/performer-init.ly (FiguredBassContext): add Figured bass for
midi