Before this change rclone would inefficiently and confusingly read all
the files in the source directory when copy or moving a single file.
This caused confusion for the users to see log messages about files
which weren't part of the sync.
After the change the copy and move commands use the new infrastructure
made for the copyto and moveto command for single file copy and move.
The purpose of this is to make it easier to maintain and eventually to
allow the rclone backends to be re-used in other projects without
having to use the rclone configuration system.
The new code layout is documented in CONTRIBUTING.
