libdraw: change DefaultDPI to 133

Let's see if that's any better.

R=rsc
http://codereview.appspot.com/6850103
diff --git a/include/draw.h b/include/draw.h
index fe059ac..d5f2ca6 100644
--- a/include/draw.h
+++ b/include/draw.h
@@ -63,7 +63,7 @@
 	Displaybufsize	= 8000,
 	ICOSSCALE	= 1024,
 	Borderwidth	= 4,
-	DefaultDPI	= 100
+	DefaultDPI	= 133
 };
 
 enum