fixed inconsitencies and usage of the idChatOpen Session variable

.../imports/api/group-chat-msg/server/handlers/userTyping.js

...ton-html5/imports/api/group-chat-msg/server/publishers.js

bigbluebutton-html5/imports/startup/client/base.jsx

...imports/ui/components/authenticated-handler/component.jsx

...tton-html5/imports/ui/components/chat/alert/container.jsx

bigbluebutton-html5/imports/ui/components/chat/container.jsx

bigbluebutton-html5/imports/ui/components/chat/service.js