update doc version to 0.9 dev

doc/conf.py

@@ -60,9 +60,9 @@ copyright = '2008--2016, LISA lab'
 # other places throughout the built documents.
 #
 # The short X.Y version.
-version = '0.8'
+version = '0.9'
 # The full version, including alpha/beta/rc tags.
-release = '0.8.0'
+release = '0.9 dev'
 
 # There are two options for replacing |today|: either, you set today to some
 # non-false value, then it is used: