API: BREAKING CHANGE: (bug 28541) Output of binary ICU sortkeys is broken. Change...

API: BREAKING CHANGE: (bug 28541) Output of binary ICU sortkeys is broken. Change sortkey fields in prop=categories and list=categorymembers to hexadecimal strings, that way we don't have any issues with scary binary stuff. Also change cmcontinue to take hex-encoded sortkeys and swap the order back to normal (previously sortkey was at the end because it could contain pipe characters, but that's not an issue with hex).