[ANN] Dhaka-2.0.1 housecleaning

This release adds no new functionality. Instead it focuses on:

* Cleaning up the code - I'm grateful to Marcel Molina, Jr for submitting a
major library-wide patch that makes the code much more idiomatic.
  The adoption of the %w syntax for grammar productions is also due to him.
* Organizing the tests - they're broken out in a way that I hope is easier
to understand.
* Extending the coverage of the tests - they're much closer to complete.
* Creating tested documentation - the pages on the website now extract code
from Dhaka's test suite, so they can't get out of sync.

New features are planned for the next release. Stay tuned, and thanks for
all the suggestions and support.

Mushfeq.