Add common Session_Process() function to allow the client and server API to co-exist in the same application

[cdewbery]

In the case where a user wants to use both the Client and Server APIs in the same application, the AwaServerSession_Process() and AwaClientSession_Process() must be called sequentially one after another to handle events. This results in the process call from the Server API blocking the Client API and vice versa. To get around this the timeout can be reduced, but this results in the main loop essentially polling the API for events, which isn't really that desirable. The API would be much improved if a common AwaSession_Process() function was introduced to handle events from both the Client and Server API.