Given absolute paths `dir` and `file`, returns the relative path of `file` relative to `dir`.

Calculate a display name for a file by figuring it out what basedir it's relative to and trimming the basedir prefix off the front.

Calculate display name for list of files.

IsChild returns true if the given file is a child of the given directory.

IsChildOfOne returns true if the given file is a child of (at least) one of the given directories.

filepath.Abs for testing.

Returns the absolute version of this path, resolving all symlinks.

Like os.Getwd, but with all symlinks resolved.

TryAsCwdChildren converts the given absolute paths to children of the CWD, if possible (otherwise, leaves them as absolute paths).