Much faster.

Should not fail now that I've adjusted the chunk size.

Implement complete close handshake

I changed my mind after #103 as browsers include a wasClean event to indicate
whether the connection was closed cleanly. From my tests, if a server using
this library prior to this commit initiates the close handshake, wasClean
will be false for the browser as the connection was closed before it could
respond with a close frame. Thus, I believe it's necessary to fully implement
the close handshake.

@stephenyama You'll enjoy this.

Add websocket.CloseStatus

Will make it much more convenient and less error prone to access
the StatusCode of a *CloseError.

Switch CI to Typescript

Integrated into the appropriate existing steps.

Significantly faster locally since **everything** runs in parallel.

Also much easier to maintain than bash.

Upload coverage.html from test.sh as an artifact

Improve usage of math/rand versus crypto/rand

math/rand was being used inappropiately and did not have
a init function for every file it was used in.

Fix WASM Subprotocol selection

Subprotocols didn't work with WASM at all before.

Very annoying.

Should prevent the sporadic failures in CI.

Closes #151

Closes #150

Fix unaligned 64 bit atomic loads on 32 bit platforms

- Also allows SetReadLimit to be called concurrently which is a nice
  touch

Closes #153