ALTQ integration

ALTQ manages output queues on network interfaces, limiting bandwidth and priorizing packets
pf is now used to define ALTQ queues and assign packets to queues
queue definition moved from /etc/altq.conf to /etc/pf.conf, pf's parser now loads the queue definitions, syntax cleaned up
'queue' option for filter rules in pf.conf assigns packets matching the rule to one or two specified queues:
normal queue for all packets
priority queue (optional) for packets that have ToS 'lowdelay' (e.g. ssh interactive) or TCP ACKs with no payload (small)