to take a single character at a time, where the character is an "int" now.
The old interface (took a string) was never called with more than 1
char to print, and the "int" allows us to handle charsets cleanly.
The graphics device driver passes a "default attribute" for normal text
output to the wscons framework. If the emulation module needs more
attributes (for different "renditions") it can allocate them via a
callback.
For now, only the "sun" emulation makes use of it.
