new NCBI Nucleotide web translator

Using the Entrez Eutils JSON API. This is a translator for datasets, and therefore has some limitations, e.g. apparently no author information.
```
var items = {}, found = false;
for (....) {
  ....
  if (id && title ) {
    found = true;
    items...
  }
}

return found ? items : false;
```