py: Improve __bool__ and __len__ dispatch; add slots for them.
diff --git a/py/qstrdefs.h b/py/qstrdefs.h
index 8170684..50b426f 100644
--- a/py/qstrdefs.h
+++ b/py/qstrdefs.h
@@ -13,6 +13,8 @@
 Q(__qualname__)
 Q(__repl_print__)
 
+Q(__bool__)
+Q(__len__)
 Q(__getitem__)
 Q(__add__)
 Q(__sub__)