Adding a tool to validate VCFs

[nh13]

There are other tools out there. The motivation for this tool are:

1. Validates the VCF header, including against spec-reserved header values (id, type, and count)
2. Validates types and counts of variants (INFO) and genotypes (FORMAT) fields versus (1)
3. Allows for custom validators across variants/genotypes
4. Allows for quickly incorporating other types of validation (all field types, across genotypes/samples/variants/fields etc)
5. Other tools may not validate the spec strictly, as they are part of Genome Analysis Tool Kits that produce variants, sometimes in non-spec compliant ways. We do not need to make those compromises
6. In Scala: succinct, concise, and performant.

[yfarjoun]

I can't read scala that fluently….so I just commented on the text… :-)

[nh13]

@yfarjoun thank-you!