Update EJS, Stylus, Sass, and LESS

For #24, adds a

* [new, minor version of EJS](https://github.com/visionmedia/ejs/blob/master/History.md#085--2013-11-21)
* ~~[new, major version of Stylus](https://github.com/LearnBoost/stylus/blob/master/History.md#0410--2013-11-30) adds the first version of `{block}`, which gives Stylus’ something like Sass’ `@contents`.~~
* [new, major version of Stylus](https://github.com/LearnBoost/stylus/blob/master/History.md#0420--2014-01-06) real support for `{block}`, lots of small fixes, support for `@require`, apparently?
* [new, major version of LESS](https://github.com/less/less.js/blob/master/CHANGELOG.md#161) adds interpolation, 20%–40% speedup (what?!), shadowdom, better errors…wow.
* [new, major version of Node-sass](https://github.com/andrew/node-sass/releases/tag/v0.8.0), changed the test for the included libsass update, adds initial sourcemap support

There’s a new version of Marked out, too, but it shouldn’t be updated until https://github.com/chjj/marked/issues/276 is closed.