add performance tests for pyspark

copied from spark tests
Merge pull request #2 from davies/pyspark

add performance tests for pyspark
Two minor changes to PySpark tests:

- Don’t specify master when creating SparkContext; this allows us to use
  the right master when running the program via spark-submit.
- Comment out the Python tests in config.py.template
  (the default template runs no tests)
Merge conflicts resolved