updating changelog for  0.8.4
updating changelog for  0.8.4

alisaifee/holmium.core,kejkz/holmium.core,kejkz/holmium.core,alisaifee/holmium.core,kejkz/holmium.core,kejkz/holmium.core,alisaifee/holmium.core,alisaifee/holmium.core