fixes#449 Lost keyboard input after suspend on Windows 10 PowerShell
fixes#148 Make tcell usable with any io.Reader and io.Writer
This introduces a new Tty interface so that applications can supply
their own implementation. This should facilitate work for applications
that wish to provide e.g. a webasm version of the terminal, or that need
to use different kinds of file plumbing.
Garrett D'Amore