LIBOMV-630: TestClient improvements (patch by Kephra Nurmi)

Improved TestClient:
added '@' as a command prefix to target one avatar only and to check, if a named avatar is logged in.

Improved TestClient to add new commands:

groupmembers GroupnameOrUUID - shows groupmembers UUIDs
grouproles GroupnameOrUUID - shows grouproles UUID and Names
invitegroup AvatarUUID GroupUUID RoleUUID* - invites an avatar into a group (without querying groupmembers first !-)

added public Dictionary<UUID, Group> GroupsCache = null; to TestClient.cs to refactor copy and paste code of group commands.
added friend.UUID to output of FriendsCommand.cs
swapped output of UUID and name in GroupsCommand.cs



git-svn-id: http://libopenmetaverse.googlecode.com/svn/libopenmetaverse/trunk@2989 52acb1d6-8a22-11de-b505-999d5b087335

Programs/examples/TestClient/Commands/Groups/JoinGroupCommand.cs

@@ -75,6 +75,7 @@ namespace OpenMetaverse.TestClient
 
             Client.Groups.OnGroupJoined -= gcallback;
             GetGroupsSearchEvent.Reset();
+            Client.ReloadGroupsCache();
 
             if (joinedGroup)
                 return "Joined the group " + resolvedGroupName;