The authors have been added to SANE standard itself, pointers to the
standard now point to the published version and/or the project that
isnow used for its maintenance as appropriate. References to input
files and installation locations have been removed.
Removed direct include of usb.h in backend since it
should be using sanei_usb. Completed prototype
of sane_exit(void) for some versions of gcc that are
strict about that.
Signed-off-by: Chris Bagwell <chris@cnpbagwell.com>