* Add a test for the dirty callback on writes
This new test just checks that a clean disk becomes dirty after a
write _and_ that the dirty callback is fired.
* Add tests for WOZ disks
The new tests verify the basic read behavior of the state sequencer on
well-behaved disks, including sync bytes and so on. Write tests are
still to come.
There's also a change to the Woz format to return the info chunk data
as well.
