Support js-yaml options

* I updated all the test to work fine.
* I updated the main script to support [js-yaml options](https://github.com/nodeca/js-yaml#safeload-string---options-).
* I updated all the dependencies.
* I removed unnecessary bower.json.
* I updated .jshintrc.
  * Now JSHint supports `mocha` option so we don't have to pre-define global variables of Mocha explicitly. 

Before merging this PR, please enable [Travis CI build](https://travis-ci.org/jonschlinkert/read-yaml/builds).
@shinnn since js-yaml uses this for error reporting and `filepath` should always be a valid path (I think, unless we're trying to parse strings too), might make sense to always pass this on the options. e.g.

```js
module.exports.sync = function (filepath, options) {
  options = xtend({filename: filepath}, options);
  var str = fs.readFileSync(filepath, options.enc || 'utf8');
  return YAML.safeLoad(str, options);
};
```
Or is there another goal here?