trafficshaper create QoS rules to limit (or reserve) traffic used
by classes of clients.

Uplink and downlink can be controled (or not controlled) independently.

Client classes are defined by its network addresses (IPv4 or IPv6). Each
client class can define absolute or relative (to wan) bandwith, and also
the use (or not) of spare wan bandwidth when avaiable.

Signed-off-by: Luiz Angelo Daros de Luca <luizluca@gmail.com>