ipset: `add()`/`delete()` methods
ipset: `add()`/`delete()` methods

+ old `delete()` renamed to `destroy()` according to ipset(8).
little-dude/pyroute2,drzaeus77/pyroute2,roolebo/pyroute2,simudream/pyroute2,vodik/pyroute2,tomislacker/python-iproute2,little-dude/pyroute2,drzaeus77/pyroute2,tomislacker/python-iproute2,vodik/pyroute2,nazarewk/pyroute2,nazarewk/pyroute2,mtiny/pyroute2,simudream/pyroute2,nazarewk/pyroute2,roolebo/pyroute2,mtiny/pyroute2,little-dude/pyroute2