Adding UrlHelper containing random logic around manipulating urls

core/API/Request.php

core/Common.php

core/SettingsPiwik.php

core/Tracker/Action.php

core/Tracker/Referrer.php

core/Url.php

core/UrlHelper.php

misc/cron/archive.php

misc/others/iframeWidget_localhost.php

plugins/Live/Visitor.php

plugins/Proxy/Controller.php

plugins/Referers/functions.php

plugins/SEO/Controller.php

plugins/SitesManager/API.php

plugins/SitesManager/Controller.php

tests/PHPUnit/Core/CommonTest.php

tests/PHPUnit/IntegrationTestCase.php