Corrections and aligning with latest Streams API specification:

- 5.2, step 10 and 6.2 step 9: “Create a new promise, "closedPromise", and store it so it can later be returned by the closed property” changed to “Create a new promise, "closedPromise", and store it so it can later be returned by the closed property and the close method”
- 5.2, step 11 and 6.2, step 10: The push() argument of the constructor's start() function has been changed to enqueue() according to latest WHAT WG Streams API specification, https://github.com/whatwg/streams.
- 5.2, step 12 and 6.2, step 11: The first argument of the constructor's write() function changed from data to chunk according to latest WHAT WG Streams API specification, https://github.com/whatwg/streams.
- 15.1: Renamed enum ReadyState to SocketReadyState in order to avoid confusion with other APIs using a readyState attribute, https://github.com/sysapps/tcp-udp-sockets/issues/68.
Interchanged the names of the ReadableStream and WriteableStream attributes according to https://github.com/sysapps/tcp-udp-sockets/issues/69
Made the UDPSocket's localAddress and localPort attributes nullable.
https://github.com/sysapps/tcp-udp-sockets/issues/70.
Merge pull request #71 from ClaesNilsson/gh-pages

Corrections and aligning with latest Streams API specification: