Make renameFile conform to the Report, throwing isPermissionError (huh?) if either argument is a directory.  Also fixed a couple of minor glitches in renameFile/Directory.
Make renameFile conform to the Report, throwing isPermissionError (huh?)
if either argument is a directory.  Also fixed a couple of minor glitches
in renameFile/Directory.

FranklinChen/Hugs,FranklinChen/Hugs,FranklinChen/Hugs,FranklinChen/Hugs,FranklinChen/Hugs,FranklinChen/Hugs,FranklinChen/Hugs