pyani v0.2.0

Version 0.2.0 introduces a number of changes with respect to the v0.1 series of releases. Notably:

• v0.2.0 is for use with Python 3
• a longstanding bug in the --fragsize option is fixed
• several pull requests for enhancements are merged
• BLAST/nucmer results are now written to a subdirectory of the output folder, and are compressed to save disk space
• a script to download publicly-available genomes from NCBI is provided