dataset of datasets for ati
xls upload functionality
handle errors in template
validate on client side as well
sanity check for user - is the right excel file submitted?
update records
try to return somewhat meaningful errors for any kind of error in the worksheet formatting.
propagate package dict unto template
dataset of datasets csv output to stdout
remove unnecessary api call
Merge pull request #2 from deniszgonjanin/master

xls uploads to upsert rows in datastore, export combined csv command