Move markerFound and markerLost event changelog notes to the newest version.

CHANGELOG.md

 # 1.6.1-dev
 
-... nothing yet
+## aframe-ar.js
+
+- aframe-ar.js - `<a-marker>` elements will emit `markerFound` and `markerLost` events, if they have `emitevents='true'` set.
+
+## Demos
+
+- Created [an example](https://jeromeetienne.github.io/AR.js/aframe/examples/marker-events.html) that demonstrates emitting events when markers are found and lost, and registering the respective event listeners.
 
 # 1.6.0
 
@@ -33,14 +39,6 @@
 
 ---
 
-# 1.5.2
-
-## aframe-ar.js
-- aframe-ar.js - `<a-marker>` elements will emit `markerFound` and `markerLost` events, if they have `emitevents='true'` set.
-
-## Demos
-- Created [an example](https://jeromeetienne.github.io/AR.js/aframe/examples/marker-events.html) that demonstrates emitting events when markers are found and lost, and registering the respective event listeners.
-
 # 1.5.1
 
 ## aframe-ar.js