Moved to separate kmscon_pty object, the interface is cleaned up.
The input/output is all byte oriented.
Does not communicate directly with the VTE subsystem but goes through the terminal. This adds a bit of boilerplate but will come in handy in the future.
Changes since V1:
All of the pty code itself is the same.
The next series (vte) is based on this branch and I haven't found any problems with it. You can see it here: https://github.com/bluetech/kmscon/tree/vte