Modernize conf.py and Makefile

Change-Id: I3d6f87c4557fded89b84522ef09d677863a62344
diff --git a/.gitignore b/.gitignore
index e35d885..ba65b13 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1 +1 @@
-_build
+/_build/