This PR implements the sendto and recvfrom_into functions in socketpool/Socket, enabling datagram send and receive. Tested on Saola 1 Wrover with Scott's modification to the Adafruit NTP library:

https://github.com/tannewt/Adafruit_CircuitPython_NTP/blob/raw_ntp/adafruit_ntp.py

Note that I had to replace instances of time.gmtime with time.localtime to get this to work, since gmtime is not implemented in Circuitpython. code.py sketch is as follows:

import wifi
import socketpool
import adafruit_ntp
import time
from secrets import secrets

# connect to wifi
print("Connecting to %s"%secrets["ssid"])
wifi.radio.connect(secrets["ssid"], secrets["password"])
pool = socketpool.SocketPool(wifi.radio)
ntp = adafruit_ntp.NTP(pool)

while True:
    print(ntp.datetime)
    time.sleep(1)