Handle 'out of frame' exon in BRAF GENCODE data

[cmdcolin]

this is improperly displayed by our amino acid CDS glyph

UCSC vs JBrowse

might be in phase column of gff, need to check

[cmdcolin]

there is no start codon there so it's a funky thing in general

[cmdcolin]

share link for checking this issue https://jbrowse.org/code/jb2/latest/?config=%2Fucsc%2Fhg38%2Fconfig.json&session=share-YFMVVUjgOR&password=5V1F1 still exists