Don't use window and document

With this change, our JavaScript can also be executed by
non-brower engines.

src/ol/browserfeature.js

@@ -16,6 +16,6 @@ ol.BrowserFeature = {
    * @type {boolean}
    */
   HAS_TOUCH: ol.ASSUME_TOUCH ||
-      (document && 'ontouchstart' in document.documentElement) ||
+      (goog.global.document && 'ontouchstart' in document.documentElement) ||
-      !!(window.navigator.msPointerEnabled)
+      !!(goog.global.navigator.msPointerEnabled)
 };

src/ol/geolocation.js

@@ -112,7 +112,7 @@ ol.Geolocation.prototype.handleTrackingChanged_ = function() {
  * @const
  * @type {boolean}
  */
-ol.Geolocation.SUPPORTED = 'geolocation' in navigator;
+ol.Geolocation.SUPPORTED = 'geolocation' in goog.global.navigator;
 
 
 /**