Use pkgutil to get package resources

[jwp]

I've seen some people complain about projects using file, and that's exactly what py-postgresql uses to get lib*.sql files.

Make a function that will try to hit pkgutil first, and fallback to file based resolution.

[jwp]

eh, we explicitly mark the distribution as not being zip safe. ISTM, if you want packed resources, you can override builtins to map to the appropriate resource.