Review what the API and downloads provide

[blakesweeney]

To look into the pombe issues I downloaded some JSON data. In it I didn't see a mention of the computed rna_type. I also didn't see it in API, eg http://rnacentral.org/api/v1/rna/URS00000265B1). We should look over these results to what changes we need to make, particularly once we have Rfam annotations as well.