If exonerate is invoked with the '--querytype [dna|protein]' option, pass
that information to the exonerate-server to avoid "Cannot use protein
query with untranslated DNA index" errors from the server when a DNA query
sequence contains >= 15% IUPAC ambiguity bases. This also guards against
the case where a protein query that has >= 85% [ACTGN] amino acids would
be interpreted as a DNA query by the server. This change required
modifying exonerate-server to accept a "querytype" param from the client.