Add serializer for Future objects

skyport.adapter.FutureSerializer
        new json serializer

skyport.network.Connection
        gson
        Add FutureSerializer as a new type adapter

skyport.network.GraphicsServer
        gson
        Add FutureSerializer as a new type adapter

skyport.test.Utils
        getMockconnection/1
        Add LoadoutMessage to mock connection.

skyport.text.GsonTest
        gson
        Add FutureSerializer as a new type adapter

        serializePlayerTest/0
        add new test to serialize a player with fields that contains
        futures.