tcmsg: fq_codel parameters encoding
tcmsg: fq_codel parameters encoding

For now with `fqc_` prefix. Maybe change the scheme?

Example of the current usage::

    from pyroute2 import IPRoute
    ip = IPRoute()
    ip.tc('add', 'fq_codel', 3737, handle='1:0', parent=0xffffffff,
          fqc_interval='40ms',
          fqc_target='2ms',
          fqc_limit=5000,
          fqc_ecn=1)

drzaeus77/pyroute2,drzaeus77/pyroute2,roolebo/pyroute2,roolebo/pyroute2