[[ Bug 10932 ]] Optimized MCBlock::fit so that it only measure text between possible break points, rather than char-by-char.
[[ Bug 10932 ]] Added override to MCField::settextatts to allow preventing relayout.
[[ Bug 10932 ]] Added handling for P_UNDEFINED to MCField::settextatts to just force a relayout in the same way as if a prop was set.
[[ Bug 10932 ]] Used new settextatts() semantics to speed up setting P_FLAGGED_RANGES.
[[ Bug 10932 ]] Added release note.
Merge branch 'bugfix-10932' into release-6.1.1