[physfs] Ruby bindings...

[Ryan C. Gordon]

...based on SWIG, are in changeset 1051:42fef01c55d6.

These replace the previous hand-written Ruby bindings (thank you, Ed!). 
I'll have to spend some time looking at the original bindings, though, 
as I'm sure they were more "Ruby-like" and I'll want to capture that 
feeling with the SWIG version, too.

Still TODO, if possible: C#, Lua, Python, PHP, Java.

--ryan.