Fixes and new features to woodwind diagrams

A collection of small fixes/features to the \woodwind-diagram markup function.

Fixes

• partially-filled keys were always shaded grey, which indicates a trill key
• accidentals were badly aligned in non-graphical mode when size != 0

Features

• respect the font-size property
• add woodwind-diagram-details property with two sub-properties
  • fill-angle to rotate partially-filled keys
  • text-trill-circled to control indication of trills in non-graphical mode