Normalize 'from' and 'to' paths

[phbernard]

When using double dots in 'from' path (eg /path/to/your/../my/files), sync-directory can have an unexpected behavior.

For example, /path/to/my/files contains a single file, myfile. Let's run sync-directory from /path/to/your/../my/files to /path/to/dest on watch mode. At launch, it creates the /path/to/dest and populates it with myfile, as expected. But when /path/to/my/files/myfile is edited, /path/to/dest is turned into a file (not a directory anymore), filled with /path/to/my/files/myfile's content. Run the same sequence again, this time with /path/to/my/files (same folder, but without the double dots), and everything works as expected. I observed this with node 14 on Windows.

I don't think it is necessary to investigate this behavior, but just conclude that double dots notation can lead to unexpected results. I noted that sync-directory is already cautious about relative paths, maybe this is related.

The solution would be to normalize paths.

[hoperyy]

Good idea! I'll think about it and upgrade sync-directory later @phbernard