veyron2/security, veyron/security: Refactor veyron2/security/util.go.

Specifics:
 - Move Label and LabelSet methods to veyron2/security/label.go
 - Move PrincipalPattern methods to veyron2/security/pattern.go
 - Move ACL methods to veyron2/security/acl.go
 - Make Matches(PublicID, PrincipalPattern) a method on PrincipalPattern,
   and add a test.
 - Rename acl.Matches to acl.CanAccess
 - Move load/save utilities into veyron/security

Change-Id: I742c5856cc4a2a1e23c26c0304c38dd2e4757930
25 files changed
tree: 978f63f01069b0ff357b954498d80fd9de49cdbe
  1. examples/
  2. lib/
  3. profiles/
  4. runtimes/
  5. security/
  6. services/
  7. tools/