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).
> If that's the case let's just hard-code to utf8.

I think it's not needed because js-yaml itself encodes the string in utf-8 before parsing.
https://github.com/nodeca/js-yaml/blob/a6cd5657603496c7128d3b9fa621ce9274283194/lib/js-yaml/loader.js#L1506