Storage API changes

[Cantor, Scott]

>I've reviewed and looks good. Since I don't fully understand the use
>cases for versioning, I trust your reasoning for dropping @Version. I
>would like to point out, though, that there is nice symmetry between
>that annotation and the JPA annotation that serves a similar purpose,
>which was my rationale for including it. (Though due to my unfamiliarity
>with use cases, I didn't have a clear picture of how to use it, so
>dropping is probably best.)

For now at least, until I write some code with all of it and see if I'm
being paranoid, I just don't have enough experience the other way yet to
feel comfortable.

The session cache is where versioning matters, primarily, so I'll probably
examine the trade-offs of using the annotations when I get to that (which
is another way of saying, I'll assign that work to myself since I'm the
most familiar with building one on top of this API).

-- Scott