Interestingly, the version in Maven is 2.9.1, but SBT outputs file to the 2.9.1.final
directory inside target.
A couple of small changes in SparkIMain were also required.
All tests pass and ./spark-shell launches successfully.
each line's object rather than a singleton object so that we can ship
these classes to worker nodes). This is pretty hairy stuff, which would
be nice to avoid in the future by integrating with the interpreter some
other way.