Add readme

README.md

@@ -9,6 +9,13 @@ pip install git+http://git.wrl.unsw.edu.au:3000/danh/pywafo.git@basic
 pip install git+http://git.wrl.unsw.edu.au:3000/danh/daqviewer.git
 ```
 
+## Note on wafo
+
+`pywafo` is part of the Wave Analysis for Fatigue and Oceanography (WAFO) project.
+[www.maths.lth.se/matstat/wafo/](http://www.maths.lth.se/matstat/wafo/)
+
+The full version of WAFO has issues on Windows, related to difficulties in building fortran modules from source. That is why the `basic` branch is used in the instructions above.
+
 ## Usage
 
 ```