v3.6.4

Revise v3.6.4

Diff since v3.6.3

Merged pull requests:

• Adjust to upcoming change in world age semantics (#864) (@Keno)
• Fix a few more tests on master (#866) (@Keno)
• Fix "juliadir" test (#867) (@Keno)

Closed issues:

• "UNHANDLED TASK ERROR: TaskFailedException" when running extra tests (#859)
• Seems like problem that Revise doesn't work in Visual Studio Code notebooks has never been fixed (#865)