(bug 29246) Edit API occasionally throws "unknown error 231". Per comment #1 on the...

(bug 29246) Edit API occasionally throws "unknown error 231". Per comment #1 on the bug and a comment in ApiEditPage, I refactored internalAttemptSave() to return a status object. However, there are so many idiosyncracies wrt how EditPage handles various errors that I decided to put the AS_* error code in $status->value (thanks Chad for that tip) and use that to decide what to do (not part of Chad's tip). The resulting code is still a mess but at least Status objects from doEdit() are propagated now, and it'll be a little bit easier to migrate internalAttemptSave() to a proper Status-based architecture in the future. Or maybe we should just throw away EditPage and start with a blank screen, that sounds appealing to me :)