(2015-04-21) RDT corrected the definitions of \nnotes and \nnnotes
HM corrected the definitions for cautionary small accidentals
RDT added \check@staff ... \fi to \@qa h, \@mca, \hs, \qqs
so that \qa, \ca, \ha, etc. can be "hidden" using \setstaffs{n}{0}
RDT incorporated tuplet.tex (approved by George Sicherman)
and introduced \txtfont to allow changing size or style
RDT introduced
\qqsk, a one-quarter notehead skip
\tqu and \tql, synonyms for \tqh and \tqb
\ztqu and \ztql, synonyms for \ztqh and \ztqb
\hpp, \qpp, \dsp, \qsp, \hsp, \qqsp for pointed rests
\nnotes, \nnnotes: abbreviations with \multnoteskip\smallvalue
and \multnoteskip\tinyvalue spacing
RDT incorporated curly.tex (approved by Mthimkhulu Molekwa)
RDT modernized the treatment of text fonts
meterfonts must be bf, even if titling fonts are rm or sc
added dynamic-mark macros \sfz \sfzp
Added to the extension library: musixppff.tex (HM), musixadf (HM),
musixplt (RDT), musixec (RDT), musixhv (RDT)
