Wrap text in README.md.

Author: mcflugen

README.md

@@ -3,16 +3,33 @@ Status](https://travis-ci.org/landlab/tutorials.svg?branch=master)](https://trav
 
 [![Landlab header](./landlab_header.png)](http://landlab.github.io)
 
-Most of these Landlab tutorials can either be read as text files or run as interactive IPython notebooks (recommended!).
-
-To run the IPython notebook tutorials locally, you can copy this [landlab/tutorials](https://github.com/landlab/tutorials) repo to your local working environment (use the ``download ZIP`` button or fork/clone, whichever is most familiar to you).
-
-Alternatively, you can also access each notebook online from [https://nbviewer.jupyter.org/github/landlab/tutorials](https://nbviewer.jupyter.org/github/landlab/tutorials) and download an individual notebook (navigate to the specific IPython notebook you want, open it, and click the download button that appears in the upper right).
-
-After downloading/cloning, navigate into your new directory (or to the directory containing your new download) from the command line in your terminal.
-
-Use the command ``$ jupyter notebook`` to launch Jupyter, the IPython notebook viewer (it will open locally in your browser). Then navigate to the ``.ipynb`` tutorial you want to run and click to open it.
-
-To run the code in the notebook, place your cursor in a code cell, hold down ``shift``, and press ``enter``. The order in which you run the cells matters. You can even experiment with typing your own code into the cell and running that.
-
-Here is a short IPython notebook tutorial along with a screencast (the tutorial uses an example with statistics, but you can substitute Landlab!): http://www.randalolson.com/2012/05/12/a-short-demo-on-how-to-use-ipython-notebook-as-a-research-notebook/
+Most of these Landlab tutorials can either be read as text files or run
+as interactive IPython notebooks (recommended!).
+
+To run the IPython notebook tutorials locally, you can copy this
+[landlab/tutorials](https://github.com/landlab/tutorials) repo to your
+local working environment (use the ``download ZIP`` button or fork/clone,
+whichever is most familiar to you).
+
+Alternatively, you can also access each notebook online from
+[https://nbviewer.jupyter.org/github/landlab/tutorials](https://nbviewer.jupyter.org/github/landlab/tutorials)
+and download an individual notebook (navigate to the specific IPython
+notebook you want, open it, and click the download button that appears
+in the upper right).
+
+After downloading/cloning, navigate into your new directory (or to
+the directory containing your new download) from the command line
+in your terminal.
+
+Use the command ``$ jupyter notebook`` to launch Jupyter, the IPython
+notebook viewer (it will open locally in your browser). Then navigate
+to the ``.ipynb`` tutorial you want to run and click to open it.
+
+To run the code in the notebook, place your cursor in a code cell,
+hold down ``shift``, and press ``enter``. The order in which you
+run the cells matters. You can even experiment with typing your own code
+into the cell and running that.
+
+Here is a short IPython notebook tutorial along with a screencast
+(the tutorial uses an example with statistics, but you can
+substitute Landlab!): http://www.randalolson.com/2012/05/12/a-short-demo-on-how-to-use-ipython-notebook-as-a-research-notebook/