[Metakit] thread safe in python

[Brian Kelley]

We can potentially get around this by opening up a metakit storage in
read-only mode.  Metakit can have multiple readers per one writer,
although this does have some issues in that if a view change is
committed the readers that use that view will show garbage.

I have been playing with a beta version of metakit that for read-only
storages, the GIL is released.  It seems to work, although I don't
quite trust it yet :)  This seems like it would be a nice compromise. 
So, who wants to help me test this?  (n.b. I think I lost the code I
implemented, so it will take a bit to hack it again)

Brian