Merge sixpair, sixpair_kbd, support Navigation controller

[mikepurvis]

Version of sixpair which pairs both sixaxis and navigation controller:

https://github.com/mikepurvis/joystick_drivers/blob/hydro-devel/ps3joy/src/sixpair.c

If you'd consider merging it and doing a new release to the PPA, I could create a PR to bring this into sixad, and add support for the keyboard PID at the same time.

[maciejkorsan]

Thank you! It helped me with my raspberry pi project :)