integrated serial mouse drivers as a feature into the firmware architecture

 * can be enabled by defining Makefile macro SERIAL_MOUSE_MICROSOFT_ENABLE or
   SERIAL_MOUSE_MOUSESYSTEMS_ENABLE.
 * Serial implementation can be chosen via SERIAL_MOUSE_USE_SOFT and
   SERIAL_MOUSE_USE_UART macros
 * UART configuration still has to be done in config.h: I added working clauses
   for both mouse protocols to ps2_usb's config.h

fixed PS/2 keyboard converter config

When using the PS/2 interrupt implementation, the DATA pin should be
PD0 as the documentation (README.md) states.

added serial mouse driver for Microsoft and Mousesystems mice

 * Both drivers use the interface defined in serial_mouse.h
 * They should work with any UART implementation (hardware/software UART)
 * The Microsoft driver is currently untested.
   The Mousesystems driver is confirmed to work.

Just ignore ADB Service Request

- to support Adjustable keyboard(composite device?)

Fix 'debug-off' target of hhkb to remove 'print'

Fix NKRO code when NKRO is disable

Fix READEM of hhkb and doc/build.md

Fix document on HHKB internal

Add HHKB JP support

- scan matrix about twice faster

Merge pull request #124 from kairyu/6kro

USB 6KRO with pseudo- or half- NKRO feature

Merge pull request #112 from shayneholmes/ee_nkro_use_reserved_bit

Adding NKRO virtual dip-switch, using existing bit in keymap byte.

Merge pull request #125 from tibounise/patch-1

Fixing typo

Merge pull request #126 from xauser/master

Added support for bpiphany's Kitten Paw controller

Added support for bpiphany's Kitten Paw controller (Costar Majestouch)

Change keymaps of M0110

Fixing typo

Fix debug print of ps2_mouse

Fix keymap of ps2_usb

Add Ctrl + Up(SpaceFN) -> PgUp

Make keymap_hhkb as default and change keymap_hasu