Clonsdale update bluetooth keyboard threading

Updated the threading in BluetoothChatService.cs to use System.Threading.Thread rather than Java.Lang.Thread.

I have also updated the method of getting the CreateRfcommSocketToServiceRecord method.
A lot of people have had issue getting the ConnectThread to work and have been using the following work around it with the following method:
http://lists.ximian.com/pipermail/monodroid/2012-September/012376.html

I've updated to use a similar method.