Remove Bio::DDBJ::XML and REST due to suspension of DDBJ Web API (WABI)

 * Remove Bio::DDBJ::XML and Bio::DDBJ::REST due to suspension of
   DDBJ Web API (WABI). DDBJ says that it is now under reconstruction
   and the API will be completely changed. Thus, I've decided to throw
   away current API client in Ruby and to implement new one with the new
   API.
 * Autoload lines in lib/bio/db/genbank/ddbj.rb are removed.
 * Tests are also removed.
Remove Bio::Blast::Remote::DDBJ, Bio::Blast.ddbj and related components

 * Remove Bio::Blast::Remote::DDBJ, Bio::Blast.ddbj and related components
   which use Bio::DDBJ::XML or Bio::DDBJ::REST.
Delete sample/demo_ddbjxml.rb which uses Bio::DDBJ::XML