Integrate with X11

[crypdick]

As per #16 (comment) I've started a fork of screenkey (at https://github.com/crypdick/silvius-screenkey), and want to have it display the buffer as you speak.

[crypdick]

Sort of implemented in crypdick@e485304. For now, it only notifies the GrammaticError Exception string, but I'm trying to figure out how to send the prediction to notify-send.

[crypdick]

crypdick@e4f1a1a now notifies whether the buffer gets accepted or not. I'd still like to implement a live preview of the buffer using screenkey.