New scheme - Shapeshifter

I'm writing a platform game that uses less than 16 colors. So of course, I thought of base16. I wrote a template for my game and starting trying out different colors within the game.

I put my default game colors into a new scheme called "shapeshifter".

I'll wait to submit a PR with the new template until the game is finished.

Screenshots: [shapeshifter](http://awes0.me/mb16-shapeshifter.png), [monokai](http://awes0.me/mb16-monokai.png), [base16-default](http://awes0.me/mb16-default.png)

Here's a shot of shapeshift with [code](http://awes0.me/screen_2013-08-02-08-23-54.png).