doc: update changelog

Signed-off-by: Markus Klotzbuecher <mk@mkio.de>

API_Changes.md

@@ -5,12 +5,16 @@ This file tracks user visible API changes.
 
 ## v0.7.0
 
+- ubxcore: `ubx_node_cleanup` changed to remove blocks and unload
+  modules, but to leaving the node intact. For destroying a node,
+  `ubx_node_rm` was introduced.
+
 - ubx.lua: `config_get` returns `nil` if a config doesn't exist
   instead of throwing and error
 
 - added `ubx-modinfo` tool for offline module introspection
 
-- lfds_cyclic: increased loglevel for buffer overflow loggin to
+- lfds_cyclic: increased loglevel for buffer overflow logging to
   NOTICE.
 
 - introduced real-time safe logging and switched core and std_blocks