Remove unused method.
Chip away at breaking out string methods from everybody's favorite Library class.
Remove unused isHtml method.
Remove unused getStringLength method.
Remove need for stripTrailingSlash method.  rtrim works for these use cases.
Break out array methods from Library.
Break out cleanPostedData method from Library.
Break out Html methods from Library.
Remove getReferrer method from Library, as it's only ever used in one place.
Docblock fixes.
Merge branch 'master' into lib-cleanup
Merge pull request #1978 from jkazimir/lib-cleanup

Some more Library.php cleanup