Cleared output of demos and wrote readme for demos

demos/Convolutional Neural Networks/feature_engineering_image_similarity.ipynb

@@ -11,7 +11,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 2,
+   "execution_count": null,
    "metadata": {},
    "outputs": [],
    "source": [