* Remove JJ50 data from YMD96
JJ50 was actually added as its own keyboard when this was added in #2546. It should have been taken out then, but wasn't.
* Update ymd96.h
- use #pragma once include guard
- remove redundant file includes
* Update LAYOUT_iso macro to K<row><col> notation
* Update LAYOUT_custom macro to K<row><col> notation
* Update LAYOUT_default macro to K<row><col> notation
* Refactor default keymap
* Rename readme file to lowercase
* Rename layers enum and default layer
- renamed layers enum to layer_names
- proposed by fauxpark in Issue 5977, and I like the idea
- https://github.com/qmk/qmk_firmware/issues/5977#issuecomment-495924338
- renamed the base layer to _DEFAULT
- I think it looks nicer.
noroadsleft