[barcode] streaming mode for pcl output

[Alessandro Rubini]

I applied the patches to the git tree, it's now published. There were
white space errors, but the code is already full of such errors.
Actually, they are easy to make and I had to tell my emacs to paint
tabs a different color in order to see them while coding -- so all older
code of mine now looks horrible to me

   Applying add streaming mode
   .dotest/patch:19: trailing whitespace.

   .dotest/patch:68: trailing whitespace.
       }
   .dotest/patch:72: trailing whitespace.
       }
   .dotest/patch:113: trailing whitespace.

   .dotest/patch:137: space before tab in indent.
           fprintf(f, "%c&a0H", 27);
   warning: squelched 3 whitespace errors
   warning: 8 lines add whitespace errors.
   Applying document streaming mode
   Applying fix doc typos

It's in the public git.  Now I think I need to place myself in the
"must check stuff and make a release" status.

Thanks for your patience up to now
/alessandro