Platform plugin example.

This project will create a shared library named platformplugin in directory $$[QT_INSTALL_PLUGINS]/webkit
that will provide combo boxes popups to QtWebKit.

QtWebKit will look for the plugins automatically so there is no need to make any other configuration to
put the plugin into use. To stop using the plugin just remove the directory $$[QT_INSTALL_PLUGINS]/webkit.

A copy of qwebkitplatformplugin.h is provided with the example, as platform plugins should not depend
on the precense of QtWebKit to build.

This plugin can provide popups for <select multiple> elements but to use this feature QtWebKit must be
compiled with NO_LISTBOX_RENDERING enabled.