spinOnce is blocking and isReadyReceive is protected

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The spinOnce method of MessageManager is blocking if no messages are currently 
available to process.  Since the purpose of such a method is generally to run 
in realtime critical time slices, such behavior probably needs to be 
redesigned.  A useful workaround seems to be preceding the call with a 
"if(connection.isReadyReceive(0))".  However, calling this explicitly under the 
current code base is impossible since the method is protected.  In my code, I 
have modified the call to be public.

Original issue reported on code.google.com by [email protected] on 23 May 2013 at 3:52