Add assembly_reports2ttl.rb

[tfuji]

assembly_reports2ttl.rb creates RDF/turtle triples from NCBI assembly_reports resource files.

• ftp://ftp.ncbi.nlm.nih.gov/genomes/ASSEMBLY_REPORTS/assembly_summary_refseq.txt
• ftp://ftp.ncbi.nlm.nih.gov/genomes/ASSEMBLY_REPORTS/All/#{id}.assembly.txt