lib: add drums/guitar support

Parse drums and guitar data from newer kernels and provide it via the
extension event interface.

Signed-off-by: Nicolas.Adenis-Lamarre <nicolas.adenis.lamarre@gmail.com>
(splitted up and minor adjustments to resemble kernel headers)
Signed-off-by: David Herrmann <dh.herrmann@gmail.com>
xwiishow: add drums and guitar support

Print drums and guitars in the lower-right corner. Use the recently
introduced xwiimote support for that.

Signed-off-by: Nicolas.Adenis-Lamarre <nicolas.adenis.lamarre@gmail.com>
(adjust to xwiimote changes and fix coding-style)
Signed-off-by: David Herrmann <dh.herrmann@gmail.com>