Libusb1

I've completed a pass at converting logitools to using libusb-1.0 instead of the original libusb.  This allows the driver to be successfully unloaded on exit (and replaced with the kernel driver) to prevent the keyboard going dead when logitoolsd exits.

I've only been able to test it on my Fedora 17 x86_64 machine, but haven't identified any problems there.