+ improved print_user_picture() to allow images with empty alt to prevent repetitive reading of usernames in jaws when username is printed next to avatar
- new gui_basic that can be used as fallback or accessible option to gui_header_js - it is not compatible with chat daemon
- todo: CSS styling, beeping, JS fallback code in view.php and noframes fallback in gui_header_js
- minor changes in messaging language strings
- minor coding style improvements