update to tcga networks

Author: marouenbg

netbooks/Welcome_to_netBooks.ipynb

@@ -30,6 +30,8 @@
     "    \n",
     "However, since token are temporary user IDs, the working space and all the files will be deleted as soon as you logout from netbooks or after your session has been idle for 2 hours. Therefore, please don't import work on netbooks as the user files are not persistent on disk. netbooks is meant for learning and exploring application cases of network biology and to promote reproducibile analyses by providing containerized software tools. Please check how to run netbooks locally or consider [Google colab](https://colab.research.google.com/notebooks/intro.ipynb#recent=true) for persistent work spaces.\n",
     "\n",
+    "All the netbooks are set with default parameters that allows to run them in a reasonable time by loading precomputed data for time-consuming steps. This can be done by selecting the `Kernel` list in the top bar and then `Restart & Run All`.\n",
+    "\n",
     "#### Run netbooks locally\n",
     "To run the netbooks on your local machine, you can clone the netbooks [GitHub repository](https://github.com/netZoo/netbooks) and install the dependencies required in the beginning of each tutorial. We've also provided links to a public AWS S3 bucket to download all the data needed to run the analysis. These files can be downloaded using the file URLs in the netbook as follows: `curl -O urlToFile`\n",
     "\n",