make it more explicit in what cases we have to flush a currently pending cue
introduce onpartialcue, only invoke oncue on fully parsed cues
report regions to the consumer
fix README
Simple test example
Fixes to testing api
Refactor runTest
Test vertical cuesettings by comparing to JSON.

I've also separated the vertical cue setting tests out into their own
vtt files and hooked them into their own JS test runner.
Introduce new test harness with test.list files.

- Test harness now recursively reads through directories with test.list files
in them and executes the tests contained within the test.list file.
- Test.list files currently can contiain further includes of test.list files
in subdirectories or information for tests that compare compare the parsed vtt
file to data in a JSON file or, alternatively, can use custom assertions contained
within a js file.