Database object interface to SwissProt retrieval

 SwissProt is a curated database of proteins managed by the Swiss
 Bioinformatics Institute. Additional tools for parsing and manipulating
 swissprot files can be found at
 ftp://ftp.ebi.ac.uk/pub/software/swissprot/Swissknife/.
 .
 Allows the dynamic retrieval of Sequence objects (Bio::Seq) from the
 SwissProt database via an Expasy retrieval.
 .
 In order to make changes transparent host type (currently only expasy)
 and location (default to Switzerland) is separated out. This allows the
 user to pick the closest Expasy mirror for running their queries.