XOR.js

I'm guessing there's a more efficient way to do this logic, but I like
the fact that this is pretty human-readable. Feedback welcome.
Merge branch 'master' of https://github.com/codefellows/sea-c11-javascript
More efficient XOR

Simplified logic after comparing to some other merged PRs.
Merge pull request #36 from jbkly/master

XOR.js