Please add support for block code element

[mathiasschopmans]

Jade recently added support for block code elements

I tried my best to write a pull-request, but my implementation sucks. Haha. Would love if someone else can have a look. :)

//- Here's my testcode which looks kind of incorrect with the current highlighter:
var page = "404"
var title = "404 · Page not found"

var peeps = ["Mathias",
  "David", "Github"];

var msg = peeps.map(function(name) {
  return "Hi " + name
}).join(", ");

---

I guess there's just a small change in unbuffered_code's begin / end needed

Thanks for your investigations!

[mathiasschopmans]

Yay! Thank you. :+1: