Fix for STR#3016: Fl_Input and Fl_Text_Editor have now the standard behavior when doing
drag-n-drop of text: if the dragged text is dropped in the widget it comes from, it's cut and pasted.

git-svn-id: http://seriss.com/public/fltk/fltk/branches/branch-1.3@10031 ea41ed52-d2ee-0310-a9c1-e6b18d33e121