adding ngs-extract-consensus tool
Merge pull request #96 from mheuer-nmdp/extract-consensus

Adding ngs-extract-consensus tool
adding test for blocked GVCF format
allow for missing genotype and for dropped trailing genotype fields
Merge pull request #98 from mheuer-nmdp/gvcf

Adding test for blocked GVCF format
fix merge
Merge pull request #100 from mheuer-nmdp/issue-99

Allow for missing genotype and for dropped trailing genotype fields