Change keymap for rn42

- rn42 doesn't support mouse button 4 and 5
- rn42 deosn't support browser back and forward

Fix consumer key bug

Add RN-42 Bluetooth module support

Change buffer size: 256 bytes

Ad hoc fix of command API

Add initial files for RN-42

Fix for new API(key_t to keypos_t)

Fix timer.h to include AVR specific header

Port action_* to mbed

Merge branch 'mbed' into dev

Add checksum tool for NXP LPC

Add LED indicator support in mbed

Port ps2_usb to mbed

Fix build files for mbed

Fix common files for mbed

Fix debug.h and remove debug_config.h

Port action_* to mbed

Fix print and timer

Port timer to mbed

Add keyboard/mbed_onekey