Use distribution reference

Remove forked reference package. Use normalized named values
everywhere and familiar functions to convert back to familiar
strings for UX and storage compatibility.

Enforce that the source repository in the distribution metadata
is always a normalized string, ignore invalid values which are not.
Update distribution tests to use normalized values.

Signed-off-by: Derek McGowan <derek@mcgstyle.net> (github: dmcgowan)

trust/trust.go

@@ -148,7 +148,7 @@ func GetNotaryRepository(streams command.Streams, repoInfo *registry.RepositoryI
 	}
 
 	scope := auth.RepositoryScope{
-		Repository: repoInfo.FullName(),
+		Repository: repoInfo.Name.Name(),
 		Actions:    actions,
 		Class:      repoInfo.Class,
 	}
@@ -166,7 +166,7 @@ func GetNotaryRepository(streams command.Streams, repoInfo *registry.RepositoryI
 
 	return client.NewNotaryRepository(
 		trustDirectory(),
-		repoInfo.FullName(),
+		repoInfo.Name.Name(),
 		server,
 		tr,
 		getPassphraseRetriever(streams),