Merge pull request #1780 from jonathan-taylor/rmagic_extension Rmagic extension to use R (the statistical package) seamlessly from IPython. The rmagic extension allows R inline code as well as cell level magics. An example notebook is provided in docs/examples/notebooks/rmagic_extension.ipynb to demonstrate its usage. Main points: 1) Allows capture of plots to R via inline png plots (like --pylab inline) 2) Allows capture of R's stdout() connection to the notebook 3) Allows simple push/pull for array data to/from R (via rpy2) with copy only on push to R -- this seems necessary.