BPC-266: add Constants.ENTER_YOUR_USER_KEY
BPC-266: first stable(working) fix
BPC-266: add minimum delay between usersInfoGetter.execute();
BPC-269: Notifications: move to LinkedHashSets& synchronized singletons.
merge BPC-266 to develop branch
merge BPC-266 to develop branch fix
Merge branch 'develop' into BPC-220