Add the dragToWithHandle method to the MoodleSelenium2Driver to be able to drag and drop Moodle elements which offer the drag handle.

Add a new method for elements which use the Moodle moodle-core-dragdrop-draghandle to use the Syn drag function which works with YUI drag and drop.

Signed-off-by: uhunkler <urs.hunkler@unodo.de>