Replace AddCallback to AddObserver in sublime_test (#427)
Replace AddCallback to AddObserver in sublime_test (#427)

codex8/lime-backend,ch1bo/lime-backend,bj7/lime-backend,limetext/backend,bj7/lime-backend,bj7/lime-backend,limetext/lime-backend,limetext/lime-backend,ch1bo/lime-backend,codex8/lime-backend,limetext/lime-backend,ch1bo/lime-backend,codex8/lime-backend,limetext/lime-backend,ch1bo/lime-backend,bj7/lime-backend,codex8/lime-backend