Add a better temp Source/Sink to the repl

This just makes it work for any data to call .toList on a TypedPipe in the REPL.

There are still open issues:

1) non-local hadoop mode?
2) what if you have multiple tail pipes in a flow? This is an issue in a repl that does not come up in a normal job. When do you run, what is the state of the other pipes?