Update CHANGELOG for v2.1.0
Update CHANGELOG for v2.1.0

ngageoint/hootenanny-ui,kartta-labs/iD,digidem/iD,ngageoint/hootenanny-ui,openstreetmap/iD,mapmeld/iD,kartta-labs/iD,1ec5/iD,openstreetmap/iD,ngageoint/hootenanny-ui,edpop/iD,bagage/iD,edpop/iD,digidem/iD,mapmeld/iD,AndreasHae/iD,1ec5/iD,mapmeld/iD,kartta-labs/iD,bagage/iD,edpop/iD,openstreetmap/iD,1ec5/iD,AndreasHae/iD,AndreasHae/iD,morray/iD,bagage/iD,morray/iD