Problem with "Wemos D1 Mini" and the Flash library.

Hi clausinus,

use require("ESP8266").getFreeFlash(); to get a array of objects with addr and length like this

// sample output 
require("ESP8266").getFreeFlash()
=[
  { "area": 487424, "length": 4096 },
  { "area": 524288, "length": 4096 },
  { "area": 1011712, "length": 36864 }
 ]