Set allow_guest=false in lightdm configuration if allow_guest
is not set to some true value.
client: add a screen script for kdump

kdump screen script is run only if puavo_kdump_kernel word is found from
/proc/cmdline. Kexec is responsible for adding puavo_kdump_kernel to the
command line when booting to dump capture kernel.
client: depend on jq
Add "nodev,nosuid" as mount options always in puavomounts.
(The Puavo web interface may be used by people who do not
know what they are doing (giving this interface to rogue
admins is not a good idea though, but that shouldn't be
done anyway)).
Merge remote-tracking branch 'origin/master' into trusty

Conflicts:
	client/templates/etc/lightdm/lightdm.conf
	debian.default/control