Update CHANGELOG.txt
Update CHANGELOG.txt

Added in all changes for 0.16.0
krainboltgreene/draper,outstand/draper,baberthal/draper,outstand/draper,drapergem/draper,SpencerCDixon/draper,donaldpiret/draper,drapergem/draper,turingschool/draper,totzyuta/draper,yui-knk/draper,baberthal/draper,jianyuan/draper,estum/draper,drapergem/draper,Bastes/draper,mallikarjunayaddala/draper,totzyuta/draper,mallikarjunayaddala/draper,chuck-john/draper,yui-knk/draper,liwangbest/draper,estum/draper,turingschool/draper,sideci-sample/sideci-sample-draper,jianyuan/draper,chuck-john/draper,liwangbest/draper,SpencerCDixon/draper,Bastes/draper