Support recursive option for File and Directory in node_io

[jathak]

Some of these now have built-in Node support (like {File,Directory}.create), while others (like Directory.list) will require implementing it manually, but not supporting this option prevents node_io from being a drop-in replacement for dart:io in many cases (like in glob, as we've found in sass/migrator#189).

For the methods we have to reimplement manually, this can be resolved with just changes to node_io, but passing the recursive option to some of the Node methods that now support it will require changes to node_interop as well.