small updates to 00_intro

* moved 00_intro_numerical_methods-extra-examples.ipynb  to extras

Author: mspieg

00_intro_numerical_methods.ipynb

@@ -1087,7 +1087,7 @@
     "#### The \"cloud\"\n",
     "\n",
     "Instead of running things locally on your machine there are a number of cloud services that you are welcome to use in order to get everything running easily:\n",
-    " - Columbia's CUIT Jupyter Hub server\n",
+    " - [<font color=red>Columbia's CUIT Jupyter Hub server</font>](https://apma4300.columbiajupyter2.org/)\n",
     " - [Google's Colaboratory](https://colab.research.google.com)\n",
     " - [Microsoft Azure Notebooks](https://notebooks.azure.com)\n",
     " - [CoCalc](https://cocalc.com/)"
@@ -1118,7 +1118,7 @@
    "source": [
     "**Clone** the repository\n",
     "\n",
-    "`$> git clone git://github.com/mspieg/intro-numerical-methods`\n",
+    "`$> git clone https://github.com/mspieg/intro-numerical-methods.git`\n",
     "\n",
     "**Pull** in new changes\n",
     "\n",