Core: Update libusb.h header in accordance with the latest USB specs
* IMPORTANT: This update fixes a typo in the API where MaxPower was being
used instead of bMaxPower, with the latter being what is actually in
the specs.
* As a result, applications that were using MaxPower need to be updated
for bMaxPower.
* If you must maintain compatibility with libusb or older versions of
libusbx, you may also want to either use a #define or copy/paste
struct libusb_config_descriptor from libusb.h under a new name, and
then use a cast on calls that require it. For more info, see the
1.0.13 release notes in the NEWS file.
* Also update copyright notice