Init. commit of (medical) image processing ipynb.
Made changes suggested by Will Trimble - change Lena for Sally Ride.
Downsampled image to sensible size and removed references to SciPy Lena.
Simplified introduction by removing complicated colourbar placement stages.
Finished cleaning up IPYNB to show Gaussian fit to background.
Merge pull request #529 from badger-d/master

Medical image processing in the IPython Notebook