mg-rast Exports

I am in the process of fixing up mg exports to genbank. I am now directly creating compressed genbank files in jobdir/genomeid.gbk.gz (bioperl lets you write into a pipe to gzip, so I'm taking advantage of that to save on the disk I/O). So the download page should return that file if it exists, and show a message about "export not ready" or somesuch if it's not there yet (this meshes with my last mail about the export being run after the metagenome is marked visible to the frontend). --bob