fix validator for proteins. remove unused parameters in validate.

[bradfordcondon]

remove qrange. switch _set_protein_gap to _set_gap for retrieving gap open/extend values.

[bradfordcondon]

sorry usually i write more in my PRs. This PR resolves issues with tripal#33
namely form submission for all blasts won't go through because protein-based ones dont properly retrieve the gap cost/extend values and the nucleotide submission won't go through because of the qrange key.

[ekcannon]

Thanks for catching that @bradfordcondon! When I made the pull request to Tripal I had a vague sense I'd missed something. The code is looking better and better.

RE: qrange and culling limit: I'm inclined to remove all mention of both and make an issue on Tripal/tripal_blast to examine them more closely, and if possible, add them to advanced options.