Fix 1198: Fix displayLilyMusic for \time and #(set-time-signature)
create TimeSignatureMusic to allow the display to work properly
* scm/define-music-callbacks.scm
Create a new file for music callbacks that are used by iterators to
create music events. Moved multimeasure rest and ottava callbacks from
scm/define-music-types.scm.
Added callback for TimeSignatureMusic.
* scm/define-music-display-methods.scm
define a display method for TimeSignatureMusic
remove extra-display-methods for ContextSpeccedMusic and Timing that
caught \time
* scm/define-music-properties.scm
define beat-structure as a music property
* scm/define-music-types.scm
Move callbacks for multimeasure rests and ottava to scm/define-music-callbacks.scm
add TimeSignatureMusic
* scm/lily.scm
Add scm/define-music-callbacks.scm to load list
* scm/music-functions.scm
replace calls to make-beam-rule-time-signature-set with calls
to make-music 'TimeSignatureMusic