moved memcached to bottom by default
scrutinizer recommended code-cleanup. No influence on dashboard.
more scrutinizer cleanup
Fix arp-module behaviour

Change the array initialization in the arp module from [] to array() to stop a 500 exception from appearing an php 5.3.

Also, check if the arp executable is in /usr/sbin/arp and if not found fall back to /sbin/arp.