Also added the "-C" option to ping and ping6 to allow
testing and demonstrating the use of this new functionality.
Changing the default interface priority with
ifconfig em0 pcp 3, and validating the prior function
with tcpdump -i em0 icmp or ( vlan and icmp ),
using the ping -C <pcp> option we can override the
interface default (or revert a flow later to resume
using the interface default.