Modify README and installation chapter

- Recommend Anaconda Python over python.org
- Also add LICENSE.md

Author: edschofield

LICENSE.md

@@ -0,0 +1,8 @@
+# Copyright
+
+[Swaroop C H](https://swaroopch.com) and others (see the GitHub
+contributors list for details).
+
+# License
+
+This book is licensed under a [Creative Commons Attribution-ShareAlike 4.0 International License](http://creativecommons.org/licenses/by-sa/4.0/).