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).
actually, can js-yaml parse anything besides a `utf8` encoded string? If that's the case let's just hard-code to utf8. But if js-yaml can parse other encodings, what if a user wants to pass options to js-yaml and set the encoding at the same time?