change keycodes and define keymap macro for AEK.

ADD: keymap macro for Apple Extended Keyboard in adb/keymap.c
FIX: keycodes for Keypad, Fn and Mousekey.

ADB to USB keyboard converter

FIX: error handling in ps2.c

added a file TODO.

changed signature of keymap_fn_layer() in keymap_skel.h.

FIX: name of mousekey macros usb_keycodes.h.

added config option: MATRIX_HAS_GHOST and fixed some on matrix.c

ADD: Build option: MATRIX_HAS_GHOST to enable ghost blocking logic.
FIX: choose matrix buffer type(uint8_t/uint16_t) automatically
     depending on column size in matrix.c.
FIX: use uint8_t insted of int in matrix.c.

add "Build your own firmware" and "Features" section to README.

add a build option: USB_EXTRA_ENABLE

add error handling to ps2_mouse

Add PS/2 mouse support to connect TrackPoint Unit.

Change build options:  Makefile and config.h. See README.

change keyboard report descriptor for NKRO.
It uses 1byte for modifiers and 15bytes(120bits) for keys now.

add build option: NKRO_ENABLE(remove: USB_12KRO)

tuning layer switch timing.

add build option USB_12KRO.

support 12KRO

add system controls(power down/wake up) from generic desktop page(HID)

add audio controls from consumer page(HID)

change hhkb/keymap

Merge branch 'led'

output previous key state on TP1684 when scaning  matrix.