[RFC] detecting "file not found" and "directory not found" exceptions on Windows

[Alexander Belchenko]

Mark Hammond пишет:
> All os.listdir() calls, and potentially others, should be wrapped with an
> exception handler similar to this.  The listdir calls mentioned are easy to
> fix - but a quick grep shows other possibly suspect cases.  Sometimes we are
> sure the parent directory exists meaning ENOENT is OK (such as
> fancy_rename), 

fancy_rename currently broken in the case when src is not exists, but dst is.
My last fixes for fancy_rename was incorrect, because Aaron forced me to made
it much wider than simply check for case-insensitiveness. I found the bug
in fancy_rename a couple of month ago.