draws text with given fore- and background colours
The attributed_text must not contain newline characters. Each character is a triple consisting of character, text colour and background colour.
The text and background colours are themself character values.
| std::draw_text | draws text at the given position |
| std::set_character_at | sets the character at the given position |
| std::set_text_colour_at | sets the foreground color at the given position |
| std::set_background_colour_at | sets the background colour at the given position |
| std_types::screen | draw the specified attributed text at the current screen position |