savez method for DataFrame, Series: porting data between python2 and python3
I find that I am sometimes working between python2 and 3 installs and using pickle for passing data is problematic. I am having a look at adding some simple functions like:

pandas.loadnpz
pandas.obj.savenpz (where obj would be DataFrame, Series, Panel etc ...)

Any opinions on this?
Is it already there and I haven't found it?
Is there a natural (efficient) place to do this? It seems the save/load are fairly generic and are attached to all PandasObjects. Maybe at the level of NDFrame would make most sense?

Also, supposing there is interest (or at least not objection) to this, is there any way to add a test for this under the current framework since the full functionality would involve the space of both python2.\* and python3.\* pandas. 
