***************************************************************************
@method _computeFullEndpointAcl
@descripton Walks back up the endpoint tree to the root and builds the
aggregate ACL for this endpoint
@returns {carbond.security.Acl}
function() {
    var endpoint = this
    var acl = endpoint.acl || null

    var parentAcl
    while (endpoint = endpoint.parent) {
      parentAcl = endpoint.acl
      if (parentAcl && parentAcl.selfAndBelow) {
        acl = this._aclAndBelow(parentAcl, acl)
      }
    }

    return acl
  }