post install: create /var/log/linuxcnc.log, make it readable, restart rsyslog
scripts/linuxcnc.in: set default for MACHINEKIT_INI

user may override this by 'export MACHINEKIT_INI=<path>'
scripts/realtime.in: point MACHINEKIT_INI to installed default unless overridden

normally realtime would inherit MACHINEKIT_INI from scripts/linuxcnc but it
might be called standalone as well so assure a sensible setting is in place
tests/halui-jogging: disable
Merge pull request #299 from mhaberler/touchups

fix missing MACHINEKIT_INI default + export, /var/log/linuxcnc.log permissions + logging