Add BOS descriptor support

Based on earlier work done on this by Maya Erez <merez@codeaurora.org>,
Nathan Hjelm <hjelmn@me.com> and Pete Batard <pete@akeo.ie>.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
examples: Add sam3u_benchmark isochronous example by Harald Welte

Copied with the author's permission under LGPL-2.1 from
usb-benchmark-project/host/benchmark.c in
git://git.gnumonks.org/sam3u-tests.git commit
74959f7ee88f1597286cd435f312a8ff52c56b7e

http://git.gnumonks.org/cgi-bin/gitweb.cgi?p=sam3u-tests.git;a=blob;f=usb-benchmark-project/host/benchmark.c;h=74959f7ee88f1597286cd435f312a8ff52c56b7e

An Atmel SAM3U test firmware is also available in the above repository.

Conflicts:
	.gitignore

Signed-off-by: Hans de Goede <hdegoede@redhat.com>