update VEP format for biotype
prioritize VEP severe impact by biotype
minor
support biotype, revise is_lof, is_exonic
load vcf for unit testing VEP impacts
add unit tests for VEP severe_impacts, impacts
update biotype column
update biotype column
update VCF with VEP annotations
Merge pull request #272 from udp3f/master

Support biotype for VEP annotations, prioritize severe impacts by biotype