gio-tool-list: Add an option to print display names
There are some GVfs locations (i.e. google-drive://, recent://), where G_FILE_ATTRIBUTE_STANDARD_NAME is something tottaly different than G_FILE_ATTRIBUTE_STANDARD_DISPLAY_NAME. Thus it would be nice to have an easy way to show the display names. The only way currently to show the display names is to use --attributes option, which is a bit cumbersome. Let's add new --show-display-names option.