Create generic super class for clients

After having discusse the first PutFileClient code, Kåre and Mikis decided that we should attempt to create a general client class/framework which could encapsulate crosscutting client concerns. These include:

• Defining/descripe a general client api template. This will properly include a simple synchronize (blocking) api and a asynchronize (with callback/listener) api allowing better insight into the status of the comminication.
• Means of separating the different conversations taking place. The proposed solution is to create a conversation handler object each time a conversation is started, which encapsulates the logic and state of the conversation. A conversation mediator takes care of dispatching messages received on the messagebus to the relevant conversation handler.
• Aynchronize (message communication) -> synchronize functionality.
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