Create keymap.md

Fix SET_DEFAULT_LAYER action and keymap of gh60

Add tap flags on record_t

Fix keymap MACRO of pc98 adn hhkb

Add MACRO action

Merge branch 'pc98_fix' into overlays

Fix software serial configure

Add serial_uart.c and use it for PC98

Add parity option in serial_soft.c

Inhibit repeating key of PC98

New keymap of PC98

Merge branch 'pc98' of github.com:tmk/tmk_keyboard into overlays

Fix debug code of serial_soft.c

Fix README and comments in action.h

Edit README of PC98

Fix softwere serial

Add keymap for PC98

Quick Fix: read scan code from PC98

Add initial files for PC98

Fix keymap of gh60 and hhkb