Change matcher to.equal to toEqual

I guess `expect` is for [jasmine](https://github.com/pivotal/jasmine]).
The jasmine wiki defines the built-in matcher as toEqual
https://github.com/pivotal/jasmine/wiki/Matchers

Not sure if it was `to.equal` in its early life in some previous version when this snippet was written.
Merge pull request #2 from tathagata/patch-1

Change matcher to.equal to toEqual