add logo blue-print with dimensions

As for the [kilogram](http://en.wikipedia.org/wiki/Kilogram) It's nice to have a reference prototype, but it's better to have spec.

This fixes that by providing the actual center an radius of each circles in the logo. And yes they are circle if you are wondering. 
I use arbitrary Units anchored in the lower left, the one my inkscape canvas gave me. The unit where rounded to the closes pixel for the positions of the guide (which should move things by less than a 512th). 

Here is a scrennshot with a 512x512unit square as eye guide. 

![capture d ecran 2014-12-13 a 18 39 48](https://cloud.githubusercontent.com/assets/335567/5424606/7c4c0f5e-82f7-11e4-99d8-62dd9067b4e6.png)

Wondering if this makes  @rgbkrk not see chompy anymore. 

I'll tackle the gradient/color another day. 
Then we can try to make the logo with matplotlib.