WifiDirectSelectionScene and NioSession fixes

Fixed improper ScrollableListPane clipping when the list fits on one
page. Fixed mixed up parameters passed to NioSession#beginCreateServer
and NioSession#beginCreateClient in WifiDrectModel. Fleeing a network
BattleScene will close the Session. Closing a Wi-Fi Direct BattleScene
will also close the Wi-Fi Direct group. Implemented NioSession#close and
closed leaking ServerSocketChannel in
NioSession#IncompleteNioServerSession#update. Stop scanning and updating
peers list after selecting one from the list and instead show the
message "Getting peer permission...".