handling qscintilla internal shortcuts and commands depending on qsci version * file-editor.cc (request_delete_start_word, request_delete_end_word, request_delete_start_line, request_delete_end_line, request_delete_line, request_copy_line, request_cut_line, request_duplicate_selection, request_transpose_line, request_comment_selected_text, request_lower_case): use constants from QsciScintillaBase and not from QsciCommand * octave-qscintilla.cc (constructor): if qscintilla is not version 2.6, search the commands for which the shortcuts has to be disabled by the shortcut itself, otherwise use the find () function; more shortcuts are disabled because the gui takes care of them * main-window.cc (construct_file_menu): add common menu into editor menu only when qscintilla is available