adds 4th edition search notebook

Author: SnShine

index.ipynb

@@ -18,6 +18,8 @@
     "\n",
     "3. [**Search**](./search.ipynb)\n",
     "\n",
+    "4. [**Search - 4th edition**](./search-4e.ipynb)\n",
+    "\n",
     "4. [**Games**](./games.ipynb)\n",
     "\n",
     "5. [**Constraint Satisfaction Problems**](./csp.ipynb)\n",
@@ -58,7 +60,7 @@
    "name": "python",
    "nbconvert_exporter": "python",
    "pygments_lexer": "ipython3",
-   "version": "3.4.3"
+   "version": "3.5.1"
   }
  },
  "nbformat": 4,