avoid creating unnecessary octave_value objects for octave_link calls * octave-link.h (octave_linke::enter_debugger_event, octave_linke::exit_debugger_event, octave_linke::update_breakpoint, octave_linke::do_insert_debugger_pointer, octave_linke::do_delete_debugger_pointer, octave_linke::do_enter_debugger_event, octave_linke::do_exit_debugger_event, octave_linke::do_update_breakpoint): Pass file and line info as string and int instead of octave_value_list. Change all callers. * octave-qt-link.h, octave-qt-link.cc (octave_qt_link::do_insert_debugger_pointer, octave_qt_link::do_delete_debugger_pointer, octave_qt_link::do_enter_debugger_event, octave_qt_link::do_exit_debugger_event, octave_qt_link::do_update_breakpoint): Likewise. * debug.h, debug.cc (location_info): Delete. * input.cc (exit_debugger_handler): New function. (get_debug_input): Use it.