added userinput

examples/userinput_example.py

+import sys, machine
+led = machine.Pin(25, machine.Pin.OUT, machine.Pin.PULL_DOWN)
+
+def userInput():
+  print("Enter on or off to set LED:")
+  input = sys.stdin.readline()
+  if input == "on\n": 
+      led.on()
+      print("LED switched ON")
+  elif input == "off\n": 
+      led.off()
+      print("LED switched OFF")
+  else: pass
+
+while True:
+  userInput()
\ No newline at end of file