Updated the remove_directory() function to clear the directory attributes before...

Updated the remove_directory() function to clear the directory attributes before trying to delete the directory. It turns out that, on the Windows platform, directories *can* be read-only - despite the fact that the Windows Explorer can NOT set (or clear) the "read-only" flag for directories and despite the fact that Windows Explorer seems to totally ignore the "read-only" fag when it has been set somehow.