tiny DRY fix in handler test
adjust comment in logo viewlet
explicitly pass SiteMembers adapter from workgroup to GroupInfo associated, to avoid re-adapting, and to share cache state
avoid re-adapting SiteMembers once for each group in roster, instead sharing one adapter instance per WorkspaceRoster instance
groups mapping IGroups now keyed by username (login name), not user id; more careful use of PAS without assuming hard-coded plugin configuration for groups