Fix --windows-mode and FilenameMapping in rpath.py.  Bug reported by
Chris Grindstaff.

Check on --verbosity.

Write some better selection test cases to test new Iterate_fast func.

---------[ Long term ]---------------------------------------

Think about adding Gaudet's idea for keeping track of renamed files.

Look into different inode generation techniques (see treescan, Dean
Gaudet's other post).