Fixed several old issues.  Fixed SpoutPlugin not being notified of GUIDownloadTerrain getting closed.  This fixes the GUI PopUp system detecting that their is already a screen open on the client.  Fixes the player texture appearing when teleporting between worlds.  Fixes Downloading Terrain screen being forced closed via a timer within NetClientHandler vs. being handled when the FlyingPacket is detected.

Signed-off-by: Mike Howe <dockter@almuramc.com>