libusb: bump version, convert to autotools, add -compat lib

Upgrade libusb to v1.0.3 and add new libusb-compat package for
compatibility with old packages that expect the pre-1.0 API.

Also update usb_modeswitch to depend on libusb-compat rather than
libusb.

Minor fixes by Thomas Petazzoni <thomas.petazzoni@free-electrons.com>.

Fixes bug #1093.

Signed-off-by: Mike Crowe <mac@mcrowe.com>