Catching up on weekend's traffic, and preparing for a release tomorrow.

Found another place where the optparse-applicative conversion broke some
command-line parsing; using git-annex metadata to dump metadata recursively
got broken. This is the second known bug caused by that transition, which
is not too surpising given how large it was.

Tracked down and fixed a [very tricky encoding problem with metadata values](http://git-annex.branchable.com/bugs/view_fails_with___34__invalid_character__34__/).

The arm autobuilder broke so it won't boot; got a serial console hooked up
to it and looks like a botched upgrade resulting in a udev/systemd/linux
version mismatch.