filesytem::directory_iterator portability

[nobody]

From the documentation: "The leaf of a path returned by dereferencing a directory_iterator will never be "." or ".."" - the current posix/windows implementation of directory_iterator assumes that the "." and ".." directories will always be the first items returned by the native platform API.  This is not a safe assumption to make and has proven incorrect on at least one Linux system.  Enclosed patch modifies the directory_iterator implementation to test for "." and ".." in m_inc() to handle this case.

Timothy M. Shead
tshead@k-3d.com