Show disabled interface when it was already part of interface group, it avoids to show a random interface instead and let user to add it by mistake. It should fix #3680
Unset iflist and iflist_disabled
Tidy up "diag_tables.php" XHTML

Add BODY tag
Add ACTION to FORM tag
Add CDATA section to SCRIPTS
Remove NAME from OPTION tag, not valid in XHTML
Update HTML Boolean operators
Add SUMMARY to TABLE
Close IMG tag and add ALT
Move closing Anchor tag into PHP staement
Change Paragraph tag to TR tag and close
Update non breaking space tag
Add missing closing FORM, closing BODY and closing HTML tags
Merge pull request #1220 from ExolonDX/branch_master_01
Include the v4 prefix on the v6 netmask to make routing more sane and alos tracking interface configurations work!
Improve /etc/sshd:

. Create ed25519 key for ssh and silent daemon
. Remove some exec() calls
. We do not need to re-create all keys if /root/.ssh/authorized_keys is
  empty
. Remove some redundancy and declare a single array with all keys
Fix typo
Add @ to silent any possible return of posix_kill
client-config-dir is also useful when using OpenVPN's internal DHCP while bridging.
glob() is already called by unlink_if_exists
Bring in proper gmirror support for the GUI and notifications.
Made a general gmirror library to perform various gmirror tasks and get information, using some of the former widget logic to start. Updated widget to use this new code.
Added a Diag > GEOM Mirrors page that displays information about existing mirrors and perform various management tasks. Current actions include rebuilding a drive, forgetting disconnected mirror drives, insert/remove, deactivate/activate, clearing medatada. It's now possible to use the GUI to rebuild a failed mirror by performing a forget, then insert action to replace a missing/dead drive.
Also included is a notification setup. Mirror status is polled every 60 seconds, and if any aspect of the mirror changes, notifications are issues that alert in the GUI and by SMTP, etc.
Drop a note on the page about how to repair a failed mirror.