Added documentation for the new --backup option.  Sorted the options alphabetically.
Added documentation for the new --backup option.  Sorted the options alphabetically.

borisschapira/hosts,maxmurder/hosts,FrancoGag/hosts,FrancoGag/hosts,StevenBlack/hosts,maxmurder/hosts,gfyoung/hosts,gfyoung/hosts,StevenBlack/hosts