Version 4 release

After a long time of waiting, CleanLinks v4 brings much more fine-grain control over which links are cleaned and how !

Thanks to a much more detailed way of approaching rules, using a hierarchical ruleset rather than a few regular expressions, CleanLinks can now clean both parameters and embedded URLs separately.

Version 4 is finally fully debugged and operational, though the default rules shipping in CleanLinks may be a little shaky still.