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

Work on killtest code - avoid returning a failure when a file is
simply skipped.

Work on WindowsTest code - avoid returning failure because symlinks,
etc., are skipped.

Look at error code, make sure filename is always mentioned (see Knops
email).

Add --list-files-changed-between or similar option, to list files that
have changed between two times

---------[ Medium term ]---------------------------------------

Add --dry-run option (target for v1.1.x)

Add # of increments option to --remove-older-than

Restore only changed files

Make argument shortcut for cstream

Make --calculate-averages work with directory_statistics file.

Write configuration file, to make sure settings like --quoting-char,
--windows-time-format, etc., don't change between sessions,
backup/restoring, etc.

---------[ 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).