Update to v2.0.0 plus an error fix.

This pull request includes the v2.0.0 tag of the wycat/handlebars repo plus an extra commit that fixes a bug in theYUI Template test suite.

The bug fix is the final commit. 
The bug can be reproduces with the following:
```
    var options = {partials: {foo: '!{{a}}!'}};
    var text = Y.Handlebars.compile('{{> foo}}', options)({a: 'foo'}, options);
```
Let me know if I need to adjust the pull request.