import old blog entries

This pull request imports the old blog entries.

~~TODO: use the comments that this pull request also imports or get them via disqus API.~~
you can remove `postsJSON` and do 

```posts = posts.map(function(post){

     ...

    return {
      htmlFile: filename,
      content: md,
      tags: '',
      date: formateDate(post_date)
    };
```