Added Luna compatiable vim-airline theme

Hello bling,

I added a theme based on a colorscheme that I had created. Hope you will merge it :smile: 

P.S. I couldn't add the gif image of the theme in the wiki, so, I'm uploading it here ! Sorry !

![test3](https://f.cloud.github.com/assets/1803997/855867/e94e5428-f530-11e2-8097-fccaa7fdfa66.gif)