Tweaked the test harness.

Now runs the three compress/decompress permutations on each file, creating a nice matrix.
Broke out the range() to make it less costly on Python 2.x.

We use range() rather than xrange(), so it pays to only call it once on 2.x.
Added back support for the -q command-line option.

It's a total no-op, but at least keeps the command-line syntax compatible with the Python driver code.
Use -q to keep the drivers quiet.
Updated documentation.

- Tests are better now.
- It works on Python 2.x and 3.x.