Update PyBADS example link with raw image link (#29)

Update PyBADS example link with raw image link for PyPI rendering

README.md

@@ -103,7 +103,7 @@ PyBADS/BADS follows a [mesh adaptive direct search](http://epubs.siam.org/doi/ab
 - In the **poll** stage, points are evaluated on a mesh by taking steps in one direction at a time, until an improvement is found or all directions have been tried. The step size is doubled in case of success, halved otherwise. 
 - In the **search** stage, a [Gaussian process](https://en.wikipedia.org/wiki/Gaussian_process) (GP) is fit to a (local) subset of the points evaluated so far. Then, we iteratively choose points to evaluate according to a *lower confidence bound* strategy that trades off between exploration of uncertain regions (high GP uncertainty) and exploitation of promising solutions (low GP mean).
 
-**Fig 1: BADS procedure** ![BADS procedure](https://github.com/acerbilab/bads/blob/master/docs/bads-cartoon.png "Fig 1: BADS procedure")
+**Fig 1: BADS procedure** ![BADS procedure](https://raw.githubusercontent.com/acerbilab/bads/master/docs/bads-cartoon.png)
 
 See [here](https://github.com/lacerbi/optimviz) for a visualization of several optimizers at work, including BADS.