Add support for policing to FW filter
Add support for policing to FW filter

Alow setting rate policing to FW filter. this is in essence acting
like::

    tc filter replace dev eth1 parent 1: protocol ip prio 1 \
        handle 0x2 fw flowid 1:2 police \
        rate 850000bit burst 1599b action drop

+pep8 fixed

tomislacker/python-iproute2,roolebo/pyroute2,drzaeus77/pyroute2,little-dude/pyroute2,little-dude/pyroute2,mtiny/pyroute2,simudream/pyroute2,nazarewk/pyroute2,roolebo/pyroute2,little-dude/pyroute2,simudream/pyroute2,nazarewk/pyroute2,tomislacker/python-iproute2,mtiny/pyroute2,nazarewk/pyroute2,vodik/pyroute2,drzaeus77/pyroute2,vodik/pyroute2