Updating GUI to allow RNA data.

Previously, the only data-type options were "Protein" and "Nucleotide",
and whenever "Nucleotide" was selected, the configuration defaulted
to "DNA". Also, the pre-run data parsing to automatically configure
SATe settings was only allowing checks for protein and DNA.

All of this has been updated. There are now three data-type options:
"DNA", "RNA", and "Protein".