Progress: Additional file copy, clone, and move changes.

Progress: Additional file copy, clone, and move changes.

Remove code relating to the recursive copy functions.
Remove the fll_file_move() function.

The fll_file_move() has some additional logic for handling a case where the return status is F_mount.
If this is still a problem then I will have to address this.
The fll_file_move() doesn't make as much sense now that thee is an fl_directory_do().
Most of the logic needed is now outside of the FLL project and inside of the projects utilizing the library.

The fl_directory_copy() function is now fully replaced by the fl_directory_do() function.
This has an upside of being more flexible but a downside of putting more of the design burden onto the caller.
This overall appears to be resulting in a cleaner and simpler design.

Move the fl_directory_do() related callbacks into a new source and header file in Featureless Make.

I have noticed a regression, of which I would wildly guess be related to the recent cache design changes, where testing Featureless Make against bzip is not working anymore.
There is a path separator at the start of the files when there should not be.
This regression is not fixed here.
I only wanted to record it.