state/api: ApiInfo.Tag now takes a Tag
Update APIInfo.Tag to names.Tag
Merge branch 'master' of https://github.com/juju/juju into 134-names-refactor-part-vii

Conflicts:
	environs/cloudinit_test.go
	provider/azure/environ_test.go
Merge pull request #305 from davecheney/134-names-refactor-part-vii

APIInfo.Tag is now a names.Tag