Adding NAT class
Includes automatic NAT feature (mn --nat) and addNAT convenience method for topologies
fixes #111
Adding NAT class
Includes automatic NAT feature (mn --nat) and addNAT convenience method for topologies
fixes #111
undoing gateway in net and removing addNAT helpers
adding internet / nat example
more NAT cleanup of net and topo
fixing --nat option in mn
small fixes for NAT
Merge branch 'master' into nat

Conflicts:
	mininet/net.py
	mininet/node.py
Merge branch 'master' into nat
adding natnet example test
moving NAT to nodelib
adding line to natnet.py
Merge pull request #353 from mininet/devel/nat

Adding NAT class to NodeLib
Fall back to chroot() if setns() fails for mnt namespace

fixes #347