Issues 305: don't overescape strings at extraction time

* We now only escape single quotes at extractions and leave other special characters alone (&\<>")
* We escape special characters at display time
* Utils::cleanSearch() renamed to Utils::cleanString() and no longer sanitize strings for security (use Utils::secureText())
* Searches for special characters such as &brandshortname; or \ now work, same for API
* Google and Bing links no longer include html entities
some strings in our repos are stored as escaped strings already, we don't want to double escape them otherwise we end up with \\\ in our strings.