Add two new Bamboo Pen & Touch models:

Bamboo Comic Medium			(CTH661/S1; Product ID = 0xd8)
Bamboo P & T Special Edition Small	(CTH461/L;  Product ID = 0xdA)
Tested-by: NIRIE Shinsuke <irieshinsuke@yahoo.co.jp>
Tested-by: NAndrea Cadeddu <mrernia@gmail.com>
Signed-off-by: NDavid Foley <favux.is@gmail.com>
Reviewed-by: NPing Cheng <pingc@wacom.com>
Signed-off-by: NDmitry Torokhov <dtor@mail.ru>