GetResponse needs a proper implementation

[justintconroy]

The current implementation just blocks until some data is received. This could be forever if the peripheral doesn't respond.

What should happen, according to the spec, is that if it takes longer than 5ms for the peripheral to respond, the VMC should interpret that as a Negative Acknowledgment. This should be returned in the error code return value for GetResponse so that the caller can take the appropriate action. Either retransmitting the original command, or hard resetting the peripheral if the maximum non-response time has passed.