1.205.4 VFS.ArchiveMember: directory operations
- at: aName
- Answer a FilePath for a file named `aName' residing in the directory
represented by the receiver.
- createDirectory: dirName
- Create a subdirectory of the receiver, naming it dirName.
- namesDo: aBlock
- Evaluate aBlock once for each file in the directory represented by the
receiver, passing its name.