[physfs] Multiple contexts in one process

[Ryan C. Gordon]

> At what point would you consider giving a solid yes / no to whether this 
> is welcome as a future feature to PhysFS? If I don't need to maintain 
> backwards compatibility I can move faster and implement a leaner API, 
> though a complete fork is something I usually prefer to keep as a last 
> resort.

I'm definitely not interested in breaking backwards compatibility, and 
I'm not sure I'm interested in the feature in general, either.

--ryan.