Fixes for node filesystem module and express3

The options and callback parameters of a lot of the read/write/watch node fs functions were wrong.

The express 3 definitions file did not support having the app listen on a socket or pass a callback to listen, and it incorrectly marked the next parameter in the callback to .use() as optional. (A function passed as a callback is free to not use next, but that's not what an optional parameter in a callback definition is supposed to signify. If it's marked as optional in the callback definition, then the callback function passed has to incorrectly define the parameter as optional too.)