Changes from MusiXTeX 120 to 121:

 + adjusted the offsets and/or vertical positions for some tremolos

 + moved \lastbarpos\lin@pos after calls to \Writ@meters
   to correct \centerbar positioning

 + copied the definition of \Hpause from musixlit.tex

 + introduced \Changeclefs, \cHpause and \centerHpause

 + replaced \smalltype\it by \txtfont in octave clef commands

 + moved definitions of \txtfont into \comput@fonts

 + added support for piano-pedal bracket notation