Bug samsonmking#16: Fix reference to image converter for 7.5" display

Bump ini from 1.3.5 to 1.3.8

Fix Gray samsonmking#1 not displaying correct

* Port color mapping example from waveshare python examples
* Add simple 4 gray example
* Restore prettier in package.json

4 color grayscale support (samsonmking#13)

* Implemented 4 Color Grayscale
* Add Waveshare 4.2" horizontal and vertical grayscale configurations

1.2.0

Minor bump version to 1.1.0

* Add support for Waveshare 7.5v2

Add npmignore

* Add repository to package.json
* Add usage to ereader README