Solving issue 2161: "Hide Filmstrip elements"

"t" has been remapped to "Ctrl+t" to show the content of the Trash
"t" now show/hide the film strip and update the size of the allocated space
"Shift-t" show/hide the film strip and keep the allocated space identical, preventing a main preview refresh

rtgui/editorpanel.h

@@ -146,6 +146,8 @@ class EditorPanel : public Gtk::VBox,
         void setParent (RTWindow* p) { parent = p; }
         void writeOptions();
 
+        void showTopPanel(bool show);
+
         // progresslistener interface
         void setProgress (double p);
         void setProgressStr (Glib::ustring str);