improve debugging with the GUI * dialog.h, dialog.cc (cd_or_addpath_dialog): New class. (QUIWidgetCreator::signal_debug_cd_or_addpath): New function. (QUIWidgetCreator::create_debug_cd_or_addpath_dialog): New signal. * file-editor-tab.h, file-editor-tab.cc (file_editor_tab::file_in_path): New function. (file_editor_tab::add_breakpoint_callback, file_editor_tab::remove_breakpoint_callback, file_editor_tab::remove_all_breakpoints_callback): Use file_in_path. Don't cd to the directory containing the file. Don't add 1 to the line number. (file_editor_tab::request_add_breakpoint, file_editor_tab::request_remove_breakpoint): Add 1 to the line number. (file_editor_tab::insert_debugger_pointer, file_editor_tab::delete_debugger_pointer, file_editor_tab::do_breakpoint_marker): Subtract 1 from line. (file_editor_tab::bp_info): Also cache full file name. Change all uses. * file-editor.h, file-editor.cc (file_editor::request_open_file, file_editor::handle_delete_debugger_pointer_request): Don't subtract 1 from line numbers. * main-window.h, main-window.cc (main_window::connect_uiwidget_links): Connect uiwidget_creator::create_debug_cd_or_addpath_dialog to main_window::handle_create_debug_cd_or_addpath_dialog. (main_window::handle_create_debug_cd_or_addpath_dialog): New function. * octave-qt-link.h, octave-qt-link.cc (octave_qt_link::do_debug_cd_or_addpath_error): New function. * load-path.h, load-path.cc (load_path::contains_canonical, load_path::do_contains_canonical): New functions. * octave-link.h (octave_link::debug_cd_or_addpath_error, octave_link::do_debug_cd_or_addpath_error): New functions.

--- a/libinterp/interpfcn/load-path.cc	Fri Apr 19 09:36:22 2013 -0400
+++ b/libinterp/interpfcn/load-path.cc	Fri Apr 19 17:36:40 2013 -0400
@@ -353,6 +353,25 @@
   return find_dir_info (dir) != dir_info_list.end ();
 }
 
+bool
+load_path::do_contains_canonical (const std::string& dir) const
+{
+  bool retval = false;
+
+  for (const_dir_info_list_iterator i = dir_info_list.begin ();
+       i != dir_info_list.end ();
+       i++)
+    {
+      if (same_file (dir, i->dir_name))
+        {
+          retval = true;
+          break;
+        }
+    }
+
+  return retval;
+}
+
 void
 load_path::move_fcn_map (const std::string& dir_name,
                          const string_vector& fcn_files, bool at_end)