refactor access point
Add download url

*not tested yet*
Comment on filter options
Refactor fsCollection and argParser
Clean clone just a bit

The clone unit and attempt functions return an empty object if source
is not an object - one could have them return undefined but mongodb and
minimongo handles undefined poorly.
I'm not sure if this is entirely correct to include failures etc. in
clone - have to investigate use cases.
I dont think it has to return anything else but:
```js
var result = cloneFileUnit(rec);
// Base reference
result.collectionName = '' + rec.collectionName;
result.bytesUploaded = defaultZero(rec.bytesUploaded);

if (_.isObject(rec.metadata)) {
result.metadata = rec.metadata;
}
```
Remove .npm folder
add .npm to gitignore