fix layout issues with offset chords & notes

[MarcSabatella]

Once again, fixing one issue led me to discover and fix a few other inter-related ones. These all have to do with the calculation of the space to the left and right of a segment, which in turn depends on space to left and right of a chord, which in turn depends on the placement of accidentals and grace notes. Each of these calculations was off in some way with respect to chords or notes with a user offset applied. Some of the grace note calculations were off even for chords with no user offset.

I won't swear it's all perfect now, but the layout behavior when moving a chord or note (user offset) should be more logical than before (either previous developments builds or 1.3), and grace note layout is improved overall.

[MarcSabatella]

Closing temporarily to add fix for http://musescore.org/en/node/15125, which is caused by the same problem (not taking chord offset into account in calculation left & right space for segment) and will be able to leverage the same code.

[MarcSabatella]

I've updated handling for lyrics as well as chordline, arpeggio, and hooks. These should all have a reasonable effect on spacing now even if the chord is offset (whether by user or because of collisions between voices). This should cover all element types that have a direct effect on chord spacing, according to my read of layoutPitch, computeMinWidth, and layoutX.

[MarcSabatella]

I think I messed up the rebasing somehow; I see commits in this branch that I did not make. Will try to fix.