Added build.gbrowse property and the write-gff target.
Added build.gbrowse property and the write-gff target.



Former-commit-id: 5a17807d3f8dd4d235b1c42e6aaa18640d4146a5
julie-sullivan/phytomine,julie-sullivan/phytomine,julie-sullivan/phytomine,julie-sullivan/phytomine,julie-sullivan/phytomine,julie-sullivan/phytomine,julie-sullivan/phytomine