Espruino on ESP32

@ollie - 8000 vars is too much.

Still seems to boot with 6000 vars. - and 7000!

>ESP32.getState();
={
  "sdkVersion": "1.0.0(c418d6b)",
  "freeHeap": 69312 }
>process.env
={
  "VERSION": "1v87.132",
  "BUILD_DATE": "Nov 28 2016",
  "BUILD_TIME": "20:47:04",
  "GIT_COMMIT": "114743c748dec1b9bc9b85fdd20ac7ccd300f5b­b",
  "BOARD": "ESP32",
  "CHIP": "ESP32",
  "CHIP_FAMILY": "ESP32",
  "FLASH": 0, "RAM": 524288,
  "SERIAL": "240ac400-2f90",
  "CONSOLE": "Serial1",
  "EXPORTS": { "jsvLock": 1074612384, "jsvLockAgainSafe": 1074612520, "jsvUnLock": 1074615156, "jsvSkipName": 1074635332,
    "jsvMathsOp": 1074646944, "jsvMathsOpSkipNames": 1074650168, "jsvNewFromFloat": 1074629948, "jsvNewFromInteger": 1074629860, "jsvNewFromString": 1074628356,
    "jsvNewFromBool": 1074629920, "jsvGetFloat": 1074640852, "jsvGetInteger": 1074634132, "jsvGetBool": 1074641544, "jspeiFindInScopes": 1074661088,
    "jspReplaceWith": 1074660836, "jspeFunctionCall": 1074671164, "jspGetNamedVariable": 1074662684, "jspGetNamedField": 1074663072, "jspGetVarNamedField": 1074663180,
    "jsvNewWithFlags": 1074627972 }
 }
>process.memory();
={ "free": 6968, "usage": 32, "total": 7000, "history": 13 }
>