scrunch

Merge pull request #421 from Crunch-io/ds-join-better-control-for-wait

Merge pull request #420 from Crunch-io/improvements-for-join-speed

Merge pull request #418 from Crunch-io/script-async-errors

update testcases

Merge remote-tracking branch 'origin/improvements-for-join-speed' into ds-join-better-control-for-wait