Fix incorrect attribute / Use template-specific version of Lo-dash

* At the current version, `readonly` attribute is mistyped and regarded as ` spellcheck=`. (See the screenshot below.) So I fixed it as [boolean attribute](http://www.w3.org/TR/html5/infrastructure.html#boolean-attribute).

  ![screenshot 2014-02-05 3 51 19](https://f.cloud.github.com/assets/1131567/2080096/25631b6c-8dd2-11e3-906b-2a356d80179b.jpg)

* I replaced [Underscore.js](http://underscorejs.org/) with the template-specific version of [Lo-dash](http://lodash.com/), which is built with `lodash include="template"` command. (See http://lodash.com/custom-builds for more details about custom build.) It includes only template engine functions and doesn't include unnecessary features.