support uploading output from a subdirectory

example:
in job template:
"outputs": {
	"otu_table.biom": {
		"directory" : "ucrC97",
 		"host": "http://#shockurl",
	}
}
at client when a workunit completes:
file $CWD/ucrC97/otu_table.biom will be uploaded to shock