Update readme
Merge pull request #5 from chrisbarnett1/master

Minor bug fix
Edited constant width and height
Edited constant width and height
Decode ean-13 part of bookland barcodes
Added sample EAN-8 images
Refactored EAN-13 checksum
Added DecodeEAN8 function
Merge branch 'ean8support' of https://github.com/chrisbarnett1/BarcodeReader into ean8support