Only benchmark the most problematic data sets.
Remove move types that have proved unhelpful.
Reduce the start date range from the left.
Don't allow the chain shift move to assign a date past the left start
range date boundary.
Make sure CH can always move up to the release date of the project.
Chain shift move will be accepted even if it goes past the minimum, but
in that case it needs to improve the start date.
ChainShiftMove now performs much better.
Fix getCriticalPathDuration()
Actually make ChainShiftMove effective.
Allow Planner to get out of precedence relationship problems.
Re-benchmark.
Newly benchmarked bests.