Added standard keyboard HID report scancode defines (thanks to László Monda).

Demos/Device/ClassDriver/Keyboard/Keyboard.c

Demos/Device/ClassDriver/KeyboardMouse/KeyboardMouse.c

...ice/ClassDriver/MassStorageKeyboard/MassStorageKeyboard.c

Demos/Device/LowLevel/Keyboard/Keyboard.c

Demos/Device/LowLevel/KeyboardMouse/KeyboardMouse.c

Demos/Host/ClassDriver/KeyboardHost/KeyboardHost.c

...assDriver/KeyboardHostWithParser/KeyboardHostWithParser.c

Demos/Host/LowLevel/KeyboardHost/KeyboardHost.c

.../LowLevel/KeyboardHostWithParser/KeyboardHostWithParser.c

LUFA/Drivers/USB/Class/Common/HID.h

LUFA/Drivers/USB/LowLevel/Host.c

LUFA/ManPages/ChangeLog.txt