fix dock widget position when being dragged out of the main window (bug #55704) * octave-dock-widget.cc (octave_dock_widget): make_window now uses a bool parameter which has to be reflected in the signal connections; (make_window): previously unused bool parameter now used for indicating the case where the widget is dragged to its floating position, get last drag position before the widget is reparented and restore geometry afeterwards or set it to the last floating position; (event): emit the signal for making a window using the appropriate flag * octave-dock-widget.h: signal queue_make_window with boolean parameter, method make_window now using its boolean paramter

--- a/libgui/src/octave-dock-widget.h	Thu Feb 28 20:40:09 2019 -0800
+++ b/libgui/src/octave-dock-widget.h	Sun Mar 03 12:56:12 2019 +0100
@@ -96,7 +96,7 @@
 
     void active_changed (bool active);
 
-    void queue_make_window (void);
+    void queue_make_window (bool widget_was_dragged);
 
     void queue_make_widget (void);
 
@@ -142,7 +142,7 @@
 
     void resizeEvent (QResizeEvent *event);
 
-    void make_window (bool not_used = false);
+    void make_window (bool widget_was_dragged = false);
 
     void make_widget (bool not_used = false);