adding circos track files
now operates on taxa.txt file that includes study counts, and writes these out to a scatter track
now operates on taxa.txt file that includes study counts, and skips taxa with 'no rank'
now operates on taxa.txt file that includes study counts, writes representation for all NCBI taxa
writes the taxa.txt file now with an extra column for study counts per taxon
now only skips *.txt files in data directory