Allow processing of all OCIDs, instead of requiring standard input

[jpmckinney]

I can get around this limitation by creating a short script to get all OCIDs:

db.mycollection.find({}, {ocid: 1}).forEach(function (item) { print(item.ocid); });

And then running:

mongo --quiet mydb myscript.js | node index.js -d mydb -c mycollection

However, it'd be nice to instead just have an option to process all OCIDs (or for this to be the default if standard input isn't provided).