The top-level README does not mention the R and Python packages

[eddelbuettel]

This is a powerful (and growing) project so documentation is always a challenge. But if someone drives by and glances at the repo they will most likely miss the fact that there are in fact two high-level helper packages here. So maybe it is time to add a paragraph or two at the top mentioning the R and Python packages, maybe also the emerging higher-level C++ binding, the tricks hiding in plain sight in the test cases, the examples etc ?

[paleolimbot]

Thanks for bringing this up! We should definitely fix this.