RingBuffer: add peek() method.

Same as get(), but doesn't advance the read pointer.
RingBuffer: add canRewind property and rewind() method

Used to undo a get(). Only permitted if the buffer isn't at capacity
and the read pointer isn't at 0.
RingBuffer: doc comments for count, isEmpty, generate.
RingBuffer: Ensure two line breaks between things.
RingBuffer: Add TODO for access qualifiers.
RingBuffer: Fix assertion message for minimum capacity.
RingBuffer: Fix inconsistent max capacity assertions.
project: Reorder test files.
RingBuffer: Attempt to handle rewinds after wrapping the read/write pointers.

Basically, this is keeps the read pointer above zero and leaves at
least enough room for `capacity` rewinds, assuming the write pointer is
at capacity.
RingBuffer: Fix conditional that should've been an error.

If, at that point, the assertion fails, something has gone wrong.
RingBuffer: add isFull property.

Does what it says.
RingBuffer: Reorder conditionals; put expected case first.
tests/RingBuffer: Add tests for isFull/isEmpty.
tests/RingBuffer: add fillTestBuffer method to do what it sounds like.

Includes tests to ensure the buffer's behaving as expected for each
test.
tests/RingBuffer: Replace duplicate code with fillTestBuffer.
tests/RingBuffer: Add testRewind method.