Fix installing to ZFS mirror / raidz with GELI encryption
Allow setting 4K block size on GPT now, and have Firefox selected
by default on installs
Since we don't have swap on installer, make sure to cap ZFS arc
size to avoid out of memory issues.
Provide a work-around for systems where GEOM is wonky, allow
the user to manually provide a target disk for grub-installs
Merge remote-tracking branch 'upstream/master'