Refactor MCFontDrawText

Text drawing requests are now done via MCDC::drawtext rather than MCFontDrawText.
Remove ::textwidth method from various drawing contexts
Remove MCGraphicContext::setfont
MCFont{Draw,Measure} text implemented in terms of MCFontBreakText

The MCFontBreakText is currently a no-op and doesn't perform any breaking
Implement text breaking for measure/draw operations

The algorithm implemented is fairly simple and will fail in various cases. It will get better when full Unicode support is added to the engine.
Bump the size of strings cachable in the measurement hash table
Speedups to OSX text rendering

Text rendering is still noticably slower than in 6.1, particularly in the script editor :-(
Fixes to Linux-specific portions of the engine
Revert accidental configuration change
Don't lay-out field contents on move

Only a re-size should trigger the layout operation.
Add bugfix note for bug 11327
Merge branch 'feature-faster_text' of https://github.com/runrevfraser/livecode into bugfix-11327
Merge branch 'bugfix-11327' into develop