Merge master to dev15.8#4997

Merged

KevinRansom merged 4 commits intodev15.8from

merges/master-to-dev15.8

May 24, 2018

Commits on May 24, 2018

Fixing #4967 (#4968)

forki
authored and
KevinRansom
committed
Remove a setify + isSingleton combo (#4980)

forki
authored and
KevinRansom
committed
Improve async stack traces (#4867)

dsyme
authored and
KevinRansom
committed
[ RFC FS-1039] implementation of value options (#4837)

dsyme
authored and
KevinRansom
committed