[PLINK-91] - Move the Credentials related classed from the IMPL to the API module
Merge pull request #62 from pedroigor/master

[PLINK-91] - Move the Credentials related classed from the IMPL to the API module
Adding support for group hierarchies when checking group membership.
Merge remote-tracking branch 'upstream2/master'
narrow membership scope for GroupRole and GroupMembership to just Agents
Adding support for group hierarchies when checking group membership.
Merge branch 'master' of github.com:pedroigor/picketlink
Adding support for group hierarchies when checking group membership.
Merge pull request #65 from pedroigor/master

Adding support for group hierarchies when checking group membership.