Spark Translation Layer 
Hey folks, I'm starting to use the pyspark.ml library and it'd be cool to create a translation layer from pandas to spark to make it easy for local code to easily translate into spark. I have two ideas and would would be great to hear feedback. If positive I'd be happy to create a PR. 

1) Direct translation  

```
spark_df = pandas_df.to_spark(spark_context)
```

2) Pseudo translation: only permit spark compatible operations on this DataFrame 

```
restricted_spark_df = pandas_df.restrict_spark()
```

Would error if any operation that would not work on a spark df were performed on this df. Harder, but potentially useful for seeing if code designed for local use can be used for spark, without even installing spark. 
