Add NDEBUG build

Change-Id: I81032fb43d6b4919bd264a644062dc31ae564427
diff --git a/src/casts.h b/src/casts.h
index 0534eca..a5e31c4 100644
--- a/src/casts.h
+++ b/src/casts.h
@@ -59,7 +59,8 @@
     implicit_cast<From*, To>(0);
   }
 
-  assert(f == NULL || dynamic_cast<To>(f) != NULL);  // RTTI: debug mode only!
+  // 
+  // assert(f == NULL || dynamic_cast<To>(f) != NULL);  // RTTI: debug mode only!
   return static_cast<To>(f);
 }