Reviewed-by: dholmes

7014948: (zipfs) ZipFileSystem.newFileSystem(Path...) should not throw FileSystemAlreadyExistsException
7015139: (zipfs) ZipPath.delete() should throw DirectoryNotEmptyException when handling "real, non-empty" dir
Summary: zip filesystem provider update
Reviewed-by: alanb

Summary: zip filesystem provider update, add zipfs.jar into ext dir
Reviewed-by: alanb

Summary: The first drop of the zip filesystem provider, as a separate demo
Reviewed-by: alanb