Update credits and release notes after manual merge of #371

CREDITS.md

@@ -48,6 +48,7 @@
 * Keith Kyzivat
 * Kevin Wojniak
 * Kimmo Mustonen
+* Lammert Bies
 * Lawrence
 * Li Peng
 * Lianghui

RELEASE_NOTES.md

@@ -5,6 +5,7 @@ Release Notes v1.9 (work in progress)
 Changes
 -------
 
+- Add API documentation
 - Use non-blocking sockets
 - stdint.h is now required and no longer optional
 - Rewrite connection close handling