Extracted the common xpaths to remove into XPATHS_TO_REMOVE.
Refactored remove_xpaths to use duck typing and read better.
Changed FullSanitizer sanitize to use tap method instead of temporary variable.
Added LinkScrubber to remove duplication in LinkSanitizer. As such made PermitScrubber easier to subclass.
Already killed off LinkScrubber. Changed it instead to be TargetScrubber, which is more general, while still allowing maximum code reuse.
Changed PermitScrubbers documentation to list override points for subclasses. Renamed should_remove_attributes? to should_scrub_attributes?.