add menu entries and shortcuts for zoom functions in the editor (bug #41516) * file-editor.cc (zoom_in): slot for zoom-in action, triggering signal for tab; (zoom_out): slot for zoom-out action, triggering signal for tab; (zoom_normal): slot for zoom-to-normal action, triggering signal for tab; (construct): new View-menu with zoom-in, zoom-out and zoom-normal entries; (add_file_editor_tab): connect zoom-signal to newly created tabs; (set_shortcuts): set shortcuts for new zoom actions; (check_actions): disable zoom action when no editor tab is open * file-editor.h: zoom-in, zoom-out and zoom-normal actions, related slots and related signals to the actual tab * file-editor-tab.cc (zoom_in): new slot for signal from file_editor; (zoom_out): new slot for signal from file_editor; (zoom_normal): new slot for signal from file_editor * file-editor-tab.h: new slots zoom_in, zoom_out, zoom_normal * octave-qscintilla.cc (constructor): disable the shortcuts qscintilla uses for the zoom-actions in order to be able to use own functions

--- a/libgui/src/m-editor/file-editor-tab.cc	Mon Mar 10 10:46:37 2014 -0500
+++ b/libgui/src/m-editor/file-editor-tab.cc	Thu Feb 13 20:39:09 2014 +0100
@@ -776,6 +776,37 @@
 
 
 void
+file_editor_tab::zoom_in (const QWidget *ID)
+{
+  if (ID != this)
+    return;
+
+  _edit_area->zoomIn (1);
+  auto_margin_width ();
+}
+
+void
+file_editor_tab::zoom_out (const QWidget *ID)
+{
+  if (ID != this)
+    return;
+
+  _edit_area->zoomOut (1);
+  auto_margin_width ();
+}
+
+void
+file_editor_tab::zoom_normal (const QWidget *ID)
+{
+  if (ID != this)
+    return;
+
+  _edit_area->zoomTo (0);
+  auto_margin_width ();
+}
+
+
+void
 file_editor_tab::handle_find_dialog_finished (int)
 {
   // Find dialog is going to hide.  Save location of window for