Introducing error handling strategies

With version 1.6.0 of RawRabbit, we introduce a new feature, Error Handling Strategy. It gives you the possibility to handle unhandled exceptions in the message handler. The default implementation, DefaultStrategy.cs has the following behavior:

• Nack the message that was being handled when the exception occurred.
• Propagate the exception back to the caller and re-throw it there, so that the requester (in the RPC scenario) doesn't need to wait for a time out exception due to request timeout.