Quarter tone

A quarter tone increase is written with a half sharp

A quarter tone lowering by half a flat;

Input is done with the accidental menu or with <ctrl-shift-#>, or <ctrl-shift-b>

Quartertones are played by MusiCAD as such, but are not taken into account in the sharps and flats automatic placement mechanism (in fact, a half sharp and a half flat are treated as a decorations)