update directory in gui after add-path/change-dir dialog * file-editor-tab.cc (file_editor_tab): get main window from editor which is given as argument; (add_breakpoint_callback, remove_breakpoint_callback, remove_all_breakpoints_callback): call file_in_path via the instance of octave_qt_link since it is not static anymore * file-editor-tab.h: include main-window.h, contructor gets editor widget as first argument, store the main window widget in a class variable * file-editor.cc (request_new_file, request_open_file): pass own pointer to a new file editor tab * main-window.cc (run_file_callback): pass the instance of octave_qt_link to the octave cmd * main-window.h: new function returning the instance of octave_qt_link * octave-cmd.cc (execute): call file_in_path via instance (not static) * octave-cmd.h: instance of octave_qt_link is given as argument and stored in a class variable * octave-qt-link.cc (file_in_path): update gui directory when user wants to change the directory * octave-qt-link.h: file_in_path is normal memebr, not static anymore