Markdown renderer

## Wish
A markdown renderer that works in combination with injection. For instance:

    <a href="content/my-content.md" class="pat-inject" data-pat-inject="trigger: autoload-visible">My content</a>

## Use cases
- Easy editing of content during the prototyping phase. Editing in markdown takes less time than editing in HTML.
- Content that is delivered in plain text can easily be pasted in a markdown file and rendered as rich text (also during proto phase). Especially when the client comes with new revisions often this is beneficial. 
- Even production could benefit from this mechanism when on production the MD files are rendered in the HTML with (maybe with nodejs) server side (for the roadmap).

## Trigger
Injection recognises a markdown file by the .md extension. Additionally, markdown parsing could be forced with an extra property on the injection trigger, like E.G. `data-type: markdown`.

## Ideas
Existing markdown rendering libs like https://github.com/evilstreak/markdown-js  could probably be used.