Trivial syntax cleanup
Disable -Ywarn-value-discard to fix non-clean builds (for now)
Revert "Disable -Ywarn-value-discard to fix non-clean builds (for now)"

This reverts commit a95562ff6452f0e1a4ad4f22615e491e4efff919.
Bump sbt.version to 0.13.6-RC3
corrected order of keys