Update example to use arrow for vectorized UDF funtime

[holdenk]

We currently have one example notebook, would be good to update the example to distribute PyArrow since this will be useful in Spark 2.3+ for vectorized UDF users.

[holdenk]

So the test now distributes Arrow, but this is still important to do in the example. It might be more powerful to do after Spark 2.3 ships so we can show a UDF before and after installing arrow :)