Adding a doc note to example.

demos/example.py

@@ -1,3 +1,19 @@
+"""
+This is a simple test of pandana functionality. If it runs with no errors
+you should see output something like:
+
+> python demos/example.py
+Generating contraction hierarchies with 4 threads.
+Setting CH node vector of size 1498
+Setting CH edge vector of size 1702
+[info src/contraction_hierarchies/src/libch.cpp:205] Range graph removed 1900 edges of 3404
+. 10% . 20% . 30% . 40% . 50% . 60% . 70% . 80% . 90% . 100%
+ 100%
+
+Depending on whether your installed copy of pandana was built with OpenMP
+support it may be run with multiple threads or only 1.
+
+"""
 import os.path
 
 import pandas as pd