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
Merge branch 'ng' -- AddrPool usage
iocore: remove IOLoop shutdown sequence from broker
python3 fixes
tests: cover remote broker shutdown
examples: push/pull both via RPC and IOcore
tests: avoid duplicate connection

FIXME!
tests: cover IPRCMD_RELOAD
iocore: ignore EBADF error on socket disconnect
iocore: remove some dead code from IOBroker
iocore: more meaningful error on link unregister in IOBroker
common: debug decorator
iocore: use of the debug decorator
examples: remove dead code
iocore: handle recv() OSError as empty read

FIXME
refactoring: exceptions in IPDB and generic parser
tests: use one process in test_ipr
tests: cover SSL connection failure

+comment about the debug decorator coverage
tests: cover connect(), disconnect(), provide(), remove()
version 0.2.6