omit icons for breakpoint markers and in documentation viewer * arrow_down.png, arrow_left.png, arrow_right.png, arrow_up.png bookmark.png, redled.png, up.png: removed obsolete icons * file-editor-tab.cc (file_editor_tab): Use qscintilla internal markers instead of icons * module.mk, resource.qrc: removed entries of obsolete icons, sort entries * parser.cc (replace_links, node_text_to_html, global_search): replace icons by html characters