modified default test height so that a single-system of double-stave fits in the default.
StaveVoices prototype, new test case for adjusting voices
use StaveVoices to format all voices at once.

Not working properly.
avoiding the call of Formatter.joinVoices() gives better joint voices!
build infrastucture
adjust measure width by staffXShift
Removed some commented lines
Merge branch 'adjust_voices'
manual hack to fix voices stretching over barlines for demo purposes
build script includes StaveVoices
ignore build