Accepts code as integers
Validate if check digit is 0
Add test for check digit 0
Add HexColor validator

This validator is useful for ensuring certain attributes should be valid
hex-color values.
Merge pull request #64 from pbechu/barcode-validator

Barcode validator : check digit 0 + barcode as integers
Merge pull request #67 from zporter/hex-color-validator

Add HexColor validator