Upgraded Jackson from 2.6.7 to 2.8.11 because of CVE-2016-7051 [#733].
Removed Files.setPosixFilePermissions method call for Windows. [#765]
Implemented disable_backfill. [#752]
Upgraded node-uuid to uuid. [#744]
Added dependencies for copied tasks for grouping task retry including nested tasks [#738]
Randomized iteration across multiple sites over the shared queue [#737]