Added unit tests to array queue
- Removed all the queue printing in the live code - too messy. Unit tests now cover it.
- Changed queue head and tail wrapping to use bitmask of arraysize-1, and forced queue size to be a power of 2 to support this
Updated README.md to report the changes since we're now bitmasking for rollover, and to mention the unit tests and power-of-2 restriction for array size