Add socket.getpeer

[Sainan]

local { scheduler, socket } = require "*"

local sched = new scheduler()
socket.bind(sched, 80, |s| -> do
    local ip, port = s:getpeer()
    local content = ip..":"..port
    s:send("HTTP/1.1 200 OK\r\nConnection: Close\r\nContent-Length: "..#content.."\r\n\r\n"..content)
end)
sched:run()