Migrated Tumblr blog to Jekyll

As discussed in the mailing list, I've migrated the posts in http://jclouds.tumblr.com to the Jekyll based jclouds-site.

This will allow us to add posts easily and have more control on them. Using Jekyll for the blog will also allow us to write posts in a collaborative way: we could push [drafts](http://jekyllrb.com/docs/drafts/) to a branch and work together in the posts.


**Note:** I've migrated all posts and re-formatted them to Markdown. There are still missing the links, I plan to add them, but I just opened the pull request to validate the look and feel and if we are comfortable with this new blog.