add doc dir to building path for example on Travis

Author: jnothman

doc/conf.py

@@ -21,6 +21,8 @@
 # add these directories to sys.path here. If the directory is relative to the
 # documentation root, use os.path.abspath to make it absolute, like shown here.
 
+# for example.py
+sys.path.insert(0, os.path.abspath('.'))
 # project root
 sys.path.insert(0, os.path.abspath('..'))