Initial tests for LedDriver
Implement LedsOffAfterCreate test
Implement TurnOnLedOne test
Implmement TurnOffLedOne test
Add circular_buffer tests and test list

This is early stage interface exploration for circular_buffer and will
be returned to later in the text. I made the decision to use a C++ class
rather than make it a C module. It will not use dynamic memory
allocation so it is suitable for embedded systems.