replace more explicit callback functions with lambda expressions * Canvas.h, Canvas.cc (Canvas::annotation_callback): Delete. Replace uses of callback functions with equivalent lambda expressions in calls to octave_link::post_event. * file-editor-tab.h, file-editor-tab.cc (file_editor_tab::add_breakpoint_event): New function. (file_editor_tab::add_breakpoint_callback, file_editor_tab::remove_breakpoint_callback, file_editor_tab::remove_all_breakpoints_callback): Delete. Replace uses of callback functions with equivalent lambda expressions in calls to octave_link::post_event. Use add_breakpoint_event to consolidate the calls to post_event for this action to a single function. * variable-editor-model.h, variable-editor-model.cc (variable_editor_model::eval_expr_event): New function. (variable_editor_model::init_from_oct): Eliminate unnecessary function parameter. (variable_editor_model::set_data_oct, variable_editor_model::eval_oct): Delete. Replace uses of callback functions with equivalent lambda expressions in calls to octave_link::post_event. Use eval_expr_event to consolidate the calls to post_event for this action to a single function.