Update Sphinx config for src/ layout

Author: mgeier

doc/conf.py

@@ -3,7 +3,7 @@
 import os
 from subprocess import check_output
 
-sys.path.insert(0, os.path.abspath('..'))
+sys.path.insert(0, os.path.abspath('../src'))
 sys.path.insert(0, os.path.abspath('.'))
 
 # Fake import to avoid actually loading CFFI and the PortAudio library