verify output files do not already exist
refactor output functions and add tests for them
add in missing files
Merge pull request #3 from bcdarwin/master

merge mvp
merge with main
adjust version requirements to compile on my machine
use error() to report problems
fix commit issue
Merge pull request #4 from j-larson/verify-files-absent

Verify files absent
four genomes; the small data set
compute scores of every pair
fix bugs in executable
make fixes portable
Merge pull request #6 from bcdarwin/investigate_memory_use

fix bugs in executable
resolve merge conflicts