zmfilter: Send message for events that are still ongoing
this adds two config options to System tab to set the default skin and css
this add some quoting, it's something debian and ubuntu packaging does, but it's pretty clear that it is good in a more general sense.
add custom lines for loading the available skins and css options
add missing commas
Don't check for zmdc.pl when stopping via systemd

If this check ever actually returns true, it makes ExecStop a no-op
and systemd will forcefully kill all processes in the service
see man systemd.service

This also prevents a deadlock when running systemctl stop,
zmpkg.pl detects bash as it's parent and attempts to call
systemctl stop itself, which blocks forever waiting for the
task it's in to complete
Merge pull request #647 from ariscop/master

Don't check for zmdc.pl when stopping via systemd
Merge pull request #645 from ZoneMinder/skin_css_default

Skin css default
Merge pull request #638 from KristofRobot/instantNotification

zmfilter: Send message for events that are still ongoing