Given a sequence or sequence entry identifer (e.g. uniprot:wap_rat), return the sequence in fasta format. If a sequence identifier, in database:identifier format, is input the EBI's WSDbfetch web service (see http://www.ebi.ac.uk/Tools/webservices/services/dbfetch) is used to retrive the sequence in fasta format. Otherwise the input is assumed to be a sequence and if passed through the Soaplab EMBOSS seqret service to force the sequence into fasta format.