Fix server list refresh and add cancellable non-blocking connection

Server list: edits and deletions now update the UI immediately by
calling SearchForGames() in ForceFriendsSessionRefresh() and
UpdateGamesList() on nav-back to LoadOrJoinMenu.

Connection: moved WinsockNetLayer::JoinGame() to a background thread
with non-blocking sockets (5s timeout, 3 retries). Users can cancel
with B/Escape during the attempt. Failed connections always show an
error dialog.

Minecraft.Client/Common/UI/UIScene_LoadOrJoinMenu.cpp

@@ -637,6 +637,11 @@ void UIScene_LoadOrJoinMenu::handleGainFocus(bool navBack)
 
         if( m_bMultiplayerAllowed )
         {
+#ifdef _WINDOWS64
+            // Refresh the games list immediately so that any server
+            // edits/deletions made in the JoinMenu are visible now.
+            UpdateGamesList();
+#endif
 #if TO_BE_IMPLEMENTED
             HXUICLASS hClassFullscreenProgress = XuiFindClass( L"CScene_FullscreenProgress" );
             HXUICLASS hClassConnectingProgress = XuiFindClass( L"CScene_ConnectingProgress" );