iproute: three new shortcut methods
iproute: three new shortcut methods

* link_names()
* link_filter()
* link_lookup()
nazarewk/pyroute2,tomislacker/python-iproute2,roolebo/pyroute2,little-dude/pyroute2,mtiny/pyroute2,nazarewk/pyroute2,simudream/pyroute2,drzaeus77/pyroute2,drzaeus77/pyroute2,little-dude/pyroute2,vodik/pyroute2,vodik/pyroute2,tomislacker/python-iproute2,little-dude/pyroute2,mtiny/pyroute2,nazarewk/pyroute2,simudream/pyroute2,roolebo/pyroute2