CFA - interfaces with CrystalFontz USB LCDs

Known to work with CFA631 and CFA635 LCDs; likely to work with others since the command sets have a lot in common. Your kernel will need the appropriate driver(s) - CDC ACM for newer LCDs, usb-serial for older.

Known issues

Some tests are occasionally flaky, and the test code is rather ugly. I wasn't sure how to fix the ugliness short of removing tests, which doesn't strike me as the best of options.