fix bug getting available operator

only use online operators
store the user whose link it was in the chat
actually store the internet db id in chat.operator_whose_link_id

but make sure to send out params[:operator_uid] in the pusher message
push out notifications for live chats on an operator online so that they can be resumed or closed
add timestamps to followup_buttons (where'd they go?)
Merge branch 'master' of https://github.com/CruGlobal/godchat