Ported r2595 from ZXing

Original commit message: "Add hint for GS1"
Ported r2596 from ZXing

Original commit message: "Patch some possible runtime exceptions in new
PDF417 code and remove some no-longer-unsupported test images"
Ported r2600 from ZXing

Original commit message: "Issue 1653 consistent interpretation of mask
penalty i: applied when 5+i=5 (i=0) consecutive modules are the same"
Ported r2618 from ZXing

Original commit message: "Escape double-angle arrow characters"