Proper compatibility for 2.6 and 2.7

As I found out today, now that I have a Mac with Lion & Python 2.7, my last pull request broke Python 2.7 compatibility. I've no idea why `platform.python_version_tuple()` returns an array of integers in 2.6 and an array of strings in 2.7, but I rewrote the if statement and it should handle both versions now.

Also updated the changelog, for kicks.