Translating FileDirectory et al to FileSystem

We're getting there! I can't believe how much effort and progress there is already.

One thing I've been noticing... when porting DirectoryEntry and subclasses to FileSystemDirectoryEntry, #name should be translated to #basename (otherwise, you get 'Directory Entry: ...', not the filename). Some of the updates (several authors) are going to have to be re-fixed because of this (I nabbed a few already). Also, FileDirectory>>pathName should become #fullName (which incidentally is pretty safe because FileDirectory>>fullName does the same thing).

Cheers,
Sean