private String clean(String in) {
        return (in == null ? "" : in.replaceAll("'", "\\'"));
    }
Cleans the given string - if it's null, it's converted to a blank string. If it has ' then those are
converted to double ' so HTML isn't screwed up.

@param in the string to clean
@return a cleaned version - not null and with escaped characters.
xmppserver/src/main/java/org/jivesoftware/admin/SubnavTag.java