Update CHANGES for 0.16.
Update CHANGES for 0.16.

Gwendocg/babeldToS,dtaht/babeld-shortrtt-metrics,jech/babeld,tcatm/babeld,Drooids/babeld,Gwendocg/babeldToS,jech/babeld,wlanslovenija/babeld,woniullb/babeld,boutier/babeld,wlanslovenija/babeld,sudomesh/babeld