Add property Session.ended

docs/api/session.md

 
 Session mode: either `"immersive"` or `"inline"`.
 
+### ended
+
+`session.ended: boolean, read-only`
+
+Whether or not the session has been ended. See also: [end](#end).
+
+*Since:* 0.3.0
+
 ### time
 
 `session.time: Time, read-only`

src/core/session.ts

     }
 
     /**
-     * Rendering viewport
+     * Whether or not the session has been ended
      */
-    get viewport(): Viewport
+    get ended(): boolean
     {
-        return this._viewport;
+        return !this._active;
     }
 
     /**
     }
 
     /**
+     * Rendering viewport
+     */
+    get viewport(): Viewport
+    {
+        return this._viewport;
+    }
+
+    /**
      * Visual cues for testing & debugging
      */
     get gizmos(): Gizmos