The plugin originally only allows HTTP URLs to be translated. With the increasing use of automatic redirection to HTTPS, this seriously restricts the utility of the plugin - neither www.kde.org nor Wikipedia can be translated.
This change enables the plugin for HTTPS URLs also. Since this can result in secure information being transmitted over the network in clear text and received by the online translation service, a warning dialogue (with the option to not ask again) is shown.
The change also removes some unused header files and ports KUrl -> QUrl, which eliminates the use of KDELibs4Support.