Got permission from Gustaf for userdiff patterns
Update Javascript userdiff driver and tests

Writing a sample Javascript driver pointed out some extra
whitespace handling that needed to be done in the diff driver.
This adds some tests with some sample javascript code that I
pulled off of GitHub just to see what would happen.  Also, to
clean up the userdiff test data, I did a "git gc" and packed
up the test objects.
Add PHP tests and fix bug in PHP builtin driver