Consider adding support for pyro to yt

[ngoldbaum]

Again, not a blocker for accepting the pyro paper.

It would be cool to add support for pyro's output format to yt. If you ever wanted to add AMR support to pyro this would make the visualization and analysis problem much easier. You might also be able to do cool in-memory analysis and visualization stuff by passing data back and forth between pyro and yt via the python process.