Merge pull request #160 from parente/badges

[ci skip] Add badges to stack READMEs

all-spark-notebook/README.md

+![docker pulls](https://img.shields.io/docker/pulls/jupyter/all-spark-notebook.svg) ![docker stars](https://img.shields.io/docker/stars/jupyter/all-spark-notebook.svg)
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 # Jupyter Notebook Python, Scala, R, Spark, Mesos Stack
 
 ## What it Gives You

datascience-notebook/README.md

+![docker pulls](https://img.shields.io/docker/pulls/jupyter/datascience-notebook.svg) ![docker stars](https://img.shields.io/docker/stars/jupyter/datascience-notebook.svg)
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 # Jupyter Notebook Data Science Stack
 
 ## What it Gives You

minimal-kernel/README.md

+![docker pulls](https://img.shields.io/docker/pulls/jupyter/minimal-kernel.svg) ![docker stars](https://img.shields.io/docker/stars/jupyter/minimal-kernel.svg)
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 # Kernel Gateway Stack
 
 ## What it Gives You

minimal-notebook/README.md

+![docker pulls](https://img.shields.io/docker/pulls/jupyter/minimal-notebook.svg) ![docker stars](https://img.shields.io/docker/stars/jupyter/minimal-notebook.svg)
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 # Minimal Jupyter Notebook Stack
 
 ## What it Gives You

pyspark-notebook/README.md

+![docker pulls](https://img.shields.io/docker/pulls/jupyter/pyspark-notebook.svg) ![docker stars](https://img.shields.io/docker/stars/jupyter/pyspark-notebook.svg)
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 # Jupyter Notebook Python, Spark, Mesos Stack
 
 ## What it Gives You

r-notebook/README.md

+![docker pulls](https://img.shields.io/docker/pulls/jupyter/r-notebook.svg) ![docker stars](https://img.shields.io/docker/stars/jupyter/r-notebook.svg)
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 # Jupyter Notebook R Stack
 
 ## What it Gives You

scipy-notebook/README.md

+![docker pulls](https://img.shields.io/docker/pulls/jupyter/scipy-notebook.svg) ![docker stars](https://img.shields.io/docker/stars/jupyter/scipy-notebook.svg)
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 # Jupyter Notebook Scientific Python Stack
 
 ## What it Gives You