Rebase GFF3 features against parent features

gff3.rebase

Version	Tool Shed	Owner	Galaxy instances where the tool is available
1.2	toolshed.g2.bx.psu.edu	iuc	usegalaxy.be
1.2	toolshed.g2.bx.psu.edu	iuc	galaxy.genouest.org usegalaxy.eu usegalaxy.fr usegalaxy.no usegalaxy.org usegalaxy.org.au