Updated HP backend to v0.86 from Peter Kirchgessner. Enable scan

depths > 8 and add option enable-image-buffering to config file.

backend/hp.desc

@@ -10,7 +10,7 @@
 ;
 
 :backend "hp"                     ; name of backend
-:version "0.85"                   ; version of backend
+:version "0.86"                   ; version of backend
 :status :beta                    ; :alpha, :beta, :stable, :new
 :manpage "sane-hp"                ; name of manpage (if it exists)
 :url "http://www.kirchgessner.net/" ; backend's web page