improve ai server
new server for ai
Revert "disable signed JS and socket hijack protection"

This reverts commit 2900eef2c3e355ff0ba8ec42e5251903dffc7170.

Conflicts:
	app/views/base/layout.scala.html
	modules/round/src/main/SocketHandler.scala
improve hijack detection
cs "česky, čeština" translation #2520. Author: Ondrej Pialek.
use new ai server
compatibility with stockfish 3