Update README for Python 3 support

Author: kzielnicki

README.md

@@ -10,15 +10,15 @@ Nodebook is a plugin for Jupyter Notebook designed to enforce an ordered flow of
 Nodebook is available on pypi and can be installed with pip. Additionally, the jupyter extension must be registered:
 ```
 pip install nodebook
-upyter nbextension install --py nodebook
+jupyter nbextension install --py nodebook
 ```
 
 ## Usage
 
 To use Nodebook, add the following lines to a cell in your Jupyter notebook:
 ```
 #pragma nodebook off
-%load_ext nodebookext
+%load_ext nodebook.ipython
 %nodebook {mode} {name}
 ```
 Where `{mode}` is one of `memory` or `disk`, and `{name}` is a unique identifier for your notebook.
@@ -31,9 +31,9 @@ For additional example usage, see [nodebook_demo.ipynb](./nodebook_demo.ipynb).
 
 ## FAQ
 
-#### Q: Does Nodebook support Python 2?
+#### Q: Should I use Python 2 or Python 3 with Nodebook?
 
-Yes, but we recommend using Python 3.
+There has been an [increasing consensus](http://www.python3statement.org/) toward sunsetting support for Python 2, including in Project Jupyter. Nodebook currently supports both Python 2 and Python 3, but Python 3 is preferred.
 
 #### Q: Why am I seeing "ERROR:root:Cell magic `%%execute_cell` not found."?