see https://discourse.mailinabox.email/t/multiple-domains-in-mail-in-a-box-with-the-domains-being-hosted-elsewhere/56/18

/proc/meminfo reports kibibytes. Lower the minimum memory requirement so that 768 MB (not MiB) also is allowed.

Report the detected memory in MB (not KiB), to be clearer.

Fixes #289.

If bind9 isn't running, dont proceed with other checks because we can't do DNS checks. Even though we skip, add error handling so that a failed call to rndc doesn't crash and that a timeout in a DNS check doesn't crash the status checks.

partialy reverts 93a722f8; closes #287

explain how to add SRV records to DNS zonefile using the API

see https://discourse.mailinabox.email/t/create-srv-record-at-the-dns-server/225

see https://discourse.mailinabox.email/t/postgrey-and-ipv6/227

See https://discourse.mailinabox.email/t/mailserver-limits/228.

see https://discourse.mailinabox.email/t/local-dns-is-not-working-was-unable-to-check-system-status/165/39

admin: ensure multiple concurrent api calls dont confuse the ajax loading indicator (track number of open requets, stop fade animation when it is time to hide)

Fix NS status check - should sort on both ends of the comparison

explain how to install a multi-domain or wildcard ssl cert; if one is installed, the Replace Cert button in the admin for non-primary domains should not replace the cert on the primary domain

add `apt-get install sudo`

not all setups have it and the miab installer depends on it

Relative hostnames have a fall-back lookup with the machine's hostname appended, which makes no sense. Add a period, e.g. "my.hostname.com" => "my.hostname.com.", to prevent that.

This caused false positive Spamhaus checks. Fixes #185.

move the mobileconfig into the conf directory as a plain XML file and handle substitutions and copying to /var in web.sh

This seemed to already be technically supported but the validation is now stricter and the admin is more helpful:

* Postfix seems to allow @domain.tld as an alias destination address but only if it is the only destination address (see the virtual man page).
 * Allow @domain.tld if it is the whole destination address string.
 * Otherwise, do not allow email addresses without local parts in the destination.
* In the admin, add a third tab for making it clear how to add a domain alias.

closes #265