Adding ADAMContig back to ADAMVariant.
Merge pull request #245 from fnothaft/variant-avdl

Adding ADAMContig back to ADAMVariant.
Making sample ID field in genotype nullable.
Merge pull request #246 from fnothaft/genotype-fix-sample-id

Making sample ID field in genotype nullable.
fix for issue244; fragments were incorrect order and only took first fragment off of a sequence
Merge pull request #247 from hammerlab/issue-244

For #244, Fragments were incorrect order and incomplete