[BRLTTY] brltty "keyboard braille device" support (and a few more things)

[Sébastien Hinderer]

Hi,

Jason White :
> A question of motivation: why would you want to accept keyboard commands when
> the braille display is not connected?

That'd be useful at least when only a speech system is used (no braille
driver at all).

> I can understand why support for keyboard commands would be desirable - some
> braille displays might not provide enough keys and switches of their own to
> cover the full set of BRLTTY commands.

It may also help non-blind developers working on accessibility to play
around with brltty.

Sébastien.