Minor fixes and simplifications

This includes the "use strict" removal. I looked at doing the refactoring suggested in #73, but it adds significant clutter. As a ligher-weight alternative, I added "use strict" to the benchmark script, which should make it easy to ensure that the code remains strict-clean.
Aha, thanks for catching my mistake! I'll submit a new pull request to fix this, and I'll add some comments and some tests to make sure we handle this correctly.