rethought workingDirectory

Overnight, I rethought how workingDirectory should work. One of my big-picture goals here is to expose things in a way which will make sense to JavaScript programmers rather than C++ programmers. To that end, I think the current working directory should be exposed as an array of pathname components rather than a set of functions. This will not only eliminate the need to understand platform differences but will also provide a single point of interface. I will need to figure out how to convince V8 to watch for changes to this array after I expose it, but I suspect that's mostly a matter of research rather than development. The enumerate functionality shouldn't be strongly associated with working directories. I think I'll probably go back to fleshing out org.icongarden.fileSystem.