wip, state objects now return a Tag not a string.
Update to latest juju/names
Refactor to use names package for Action ID
Break monolithic state ParseTag test into smaller chunks. Add missing doc comment
Merge pull request #116 from johnweldon/action-names

Refactor to use names package for Action Id

Moved some of the Action Id code out into the names package, and made Action implement Entity (Tag())
Fix tests
Merge branch 'master' of https://github.com/juju/juju into 107-parsetag-redux

Conflicts:
	dependencies.tsv
	state/state_test.go
Merge pull request #119 from davecheney/107-parsetag-redux

Entity.Tag() now returns names.Tag

Wow. This massive changeset is all just to redefine
```
type Entity interface {                                                                                                                                                  
        Tag() string                                                                                                                                                 
}
```
to 
```
type Entity interface {                                                                                                                                                  
        Tag() names.Tag                                                                                                                                                 
}
```
The resulting explosion of `.String()` calls is worse than it looks and will go away in the next PR.