Fixed a problem that some Scrapbook additions (such as sticky comments) cannot be correctly removed, and a problem that some objects are not correctly removed with "Remove All Scrapbook Additions" command.

- merge "sticky-absolute" and "sticky-relative" to "sticky", no longer use "sticky-header" and "sticky-footer" as sb-obj
- rename "stripNode" to "unwrapNode"
Undo button can now be disabled whenever no history is unavailable. Editing inline annotation and editing or moving sticky annotation can now be undone.
Fixed an issue that deleting data with sub-directories gets an error.
Fixed an issue that selecting multiple folders to delete gets no error message. ERROR_MULTIPLE_SELECTION no more mention about move since it's OK.
Locale now fallbacks to en-US if not found in the specified locale.