PDF417 optimised encoding.
Merge pull request #31 from bwipp/pdf417_encode

PDF417 optimised encoding.
New release.
Update changelog.
MicroPDF417 optimised encoding.
QR Code optimised encoding.
Add QR Code proofs to contrib.
Minor update to olddocs.
Bump version for new release.
Fix issue with short inputs beginning with alpha characters.
Merge branch 'master' into datamatrix_encode