Rename rt_* to mp_*.
Mostly just a global search and replace. Except rt_is_true which
becomes mp_obj_is_true.
Still would like to tidy up some of the names, but this will do for now.
diff --git a/py/obj.h b/py/obj.h
index a8cde46..6e334e1 100644
--- a/py/obj.h
+++ b/py/obj.h
@@ -308,6 +308,7 @@
void mp_obj_print(mp_obj_t o, mp_print_kind_t kind);
void mp_obj_print_exception(mp_obj_t exc);
+int mp_obj_is_true(mp_obj_t arg);
bool mp_obj_is_callable(mp_obj_t o_in);
machine_int_t mp_obj_hash(mp_obj_t o_in);
bool mp_obj_equal(mp_obj_t o1, mp_obj_t o2);