add openvswitch support.
Explain in the doc how to attach a container to Open vSwitch bridge
Merge pull request #15 from PeerXu/master

Add support for openvswitch.
Check for eth1/carrier instead of eth1/operstate

eth1/operstate seems to be 'unknown' sometimes, even if the interface
is up and working as expected.
Merge pull request #19 from discordianfish/check-for-carrier-instead-of-operstate

Check for eth1/carrier instead of eth1/operstate.
Merge remote-tracking branch 'upstream/master' into for-centos

Conflicts:
	pipework
rebase master