Feature: Option to set the window title to the file name.

[ghost]

Alongside adding another argument, uses the following code to do so:

if let Some(filename) = self.file.as_ref().and_then(|path| path.file_name().and_then(|filename| filename.to_str())) {
    if self.window_title_filename {
        window_title = Some(filename.to_string());
    }
}

The displayed filename is the base name of the file entered with the FILE argument.