Introduce gulp build process.
Rebuild minified files.
Update Objective-C rules based on #291
Merge pull request #297 from uranusjr/objc-291

Update Objective-C rules based on #291
Fix hidden line numbers

The issue is that the `<code>` element needs the `overflow: scroll` (since the code block has a `max-height`). So the line numbers container, which is positioned absolutely using a negative left position is hidden.

This is fixed by changing the way the `<code>` element is positioned: not with a margin and a small size, but with the padding & a larger container.
Further improvements of the coy themes

* Shadows are now visible again!
* Small code cleanup (removed now unnecessary outer `max-height`)
Merge pull request #301 from apfelbox/coy-line-numbers

Fix hidden line numbers in coy theme
Fix small scrollbar issue in the coy theme
Coy theme: Fix issue with defined height of the <pre> tag

* The max-height on the `<pre>` is if there is no defined height.

The definitions of the code ensure, that the contents stay inside the `<pre>`. The `width: 100%` is need if there is no defined height of the `<pre>`, see http://stackoverflow.com/questions/14262938/child-with-max-height-100-overflows-parent.
Merge pull request #303 from apfelbox/coy-improvements

Small improvement on the horizontal scroll bar of the coy theme
Fix workers

The issue is that in workers `window` is undefined.
Therefore, in the first line, `self` will be set to `{}`.

This will destroy the check for workers later on:
```js
if (!self.document) {
	if (!self.addEventListener) {
		// in Node.js
		return self.Prism;
	}
 	// In worker
 	// ...
}
```

because `self.addEventListener` will then be undefined (due to `self = {}`).

The fix is to make the check for the environment more clever:

1. check for the browser: `(typeof window !== 'undefined')`
2. check for a worker: `(typeof WorkerGlobalScope !== 'undefined' && self instanceof WorkerGlobalScope)` (from http://stackoverflow.com/questions/7931182/reliably-detect-if-the-script-is-executing-in-a-web-worker)
3. assume we are in node
Don't set the `self` variable with `var`

Firefox directly shadows the global variable `self` if it is present (= in a worker). So we need to set `self` without `var self` but directly.
Merge pull request #304 from apfelbox/worker-fix

Fix workers & download page
Added Twig language
Merge pull request #305 from brandonkelly/gh-pages

Added Twig language
Fix conflicts.
Bump dev dependencies.
Merge pull request #269 from ben-eb/build-proc

Introduce a build process using gulp.js
Added default gulp task

It just builds components, plugins and the main prism.js file.
Fix link to Kevin Lorenz' Website + removed whitespace