Update package paths to github.com/juju/affinity
s/AGPL/LGPL/
Add juju-core test dependency version.
Hierarchical resources.

Add support for granting roles on resources that contain other
resources. Permissions on a containing resource are conferred onto
the contained resources. Containment relations are traversed through
Resource.ParentOf(). Added new Futurama test case and improved existing
ones. Made the group service resource a container over all groups.
Disambiguate RBAC interfaces. Add Access.HasGrant.

The identifer method Name() is too ambiguous among Permission and Role
interfaces. One could pass a Role as a Permission, since Role provides a
superset of Permission's methods. Using Perm() for the Permission name
and Role() for the Role name to enforce proper usage.

Also added Access.HasGrant, which tests for a role grant to a principal
on a resource or its containers.
Added affinityId cookie
Merge pull request #4 from AndrewWDeane/master

Added affinityId cookie (and note to obfuscate the id)