fixed a crash with marking a social feed story as unread
fixed a crash when sharing a story from the social feed that wasn't
shared by a friend (and set the source user to the non-friend who shared
it, if possible)
Refactoring mark feed as read to allow for non-active feeds to be marked as read. Need to do mark story as read and saved stories.
Merge pull request #412 from vpatil/ios7

iOS: Crashes when sharing or marking unread a story on the social feed