Updated to support Defold 1.8.0

CHANGE: This version works on Defold 1.8.0 and above

Removed limit on received message length

3.2.0

Removed hard length limit for received messages (#51)

Return connection close code in callback

NEW: The callback will now include the close code received when the connection was closed.

local function websocket_callback(self, conn, data)
	if data.event == websocket.EVENT_DISCONNECTED then
		print(data.code)
		print(data.message)
	end
end

Removed old api from internal code

Works with 1.2.182

Make sure to always close the connection

FIX: The connection didn't shut down properly if closed during handshake.

Fix crash on Android due to thread name length being too long

FIX: The connection thread name was longer than the allowed 16 characters.

Moved DNS lookup from main thread to reduce ANRs

Run DNS lookup in a separate thread (#37)

* Moved connection pool dial to a thread
* Make sure to join the thread when done
* Cleanup in AppInitialize. Early exit if pool creation failed.
* Only check connection timeout for emscripten

Include the specified port when connecting on HTML5

FIX: The port was ignored when connecting to a URL in HTML5 builds

Switched to direct use of the JavaScript WebSocket API in HTML5 builds

CHANGE: The extension now uses the Emscripten WebSockets API wrapper for HTML5 builds instead of POSIX TXP Socket emulation. This fixes previous issues with not being able to send text frames (messages).
FIX: Close socket connection when destroying the connection instead of returning it back to the connection pool (Thanks to @a-palagin)

Added response headers to error callback when handshake fails

Requires Defold 1.2.179 due to the header: dmsdk/dlib/http_client.h