The CHANGELOG.md file lists major changes to the codebase with each version,
with the most recent version first.
The lib/ directory contains all of the C++ code.
The khmer/ directory contains the khmer package (khmer/__init__.py,
etc) and the C++-to-Python bridge (khmer/_khmer.cc).
The scripts/ and sandbox/ directory contain Python command-line scripts.
The tests/ directory contains all of the tests. Each test is a function in
one of the tests/test*.py files.