[Sketches] Preliminary COG G2 support demo2/EPD2

**this is a work in progress**

Separate EPD2 class implements the waveform to drive the COG G2
and the v230 film.

Currently only enough of the EPD driver to do the image from MCU flash
has been transferred, enough to allow a version of demo.ino - called
demo2.ino to run

Signed-off-by: Christopher Hall <christopherhall.hsw@gmail.com>