netlink: use the same class for msg and nla
netlink: separate common netlink transport
taskstats: implementation draft
tests: pep8 issue
netlink: documentation update and codestyle fix

" → '
rtnl: reorganize the module structure
tests: rtmsg update
generic: align NLA chain
generic: provide parent for encoding NLA:s too
generic: use self['value'] for raw value

to be fixed?
generic: encode for ipaddr, l2addr types
iproute: add_addr(), del_addr() methods
generic: pep8 issues
iproute: add/del route routines
README update
iproute: link() method and change naming scheme
iproute: continue to change naming scheme

three general methods:
 * link()
 * addr()
 * route()

shortcuts: addr_add(), addr_del(), route_add(), route_del(), link_up(), link_down(),
  link_rename(), link_remove()

listing methods: get_links(), get_routes(), get_neighbors(), get_addr()

 * in-code documentation updated
 * tests removed (actually, they should be replaced later)
iproute: three new shortcut methods

* link_names()
* link_filter()
* link_lookup()
generic: error handling
README update