Fix path to source code in docs config.

This should fix API docs, which went AWOL with yesterday's changes.

docs/source/conf.py

@@ -14,7 +14,7 @@
 #
 import os
 import sys
-sys.path.insert(0, os.path.abspath('../..'))
+sys.path.insert(0, os.path.abspath('../../src'))
 
 
 # -- Project information -----------------------------------------------------