Added user typing feature to chat.

...in/scala/org/bigbluebutton/core/apps/chat/ChatApp2x.scala

...g/bigbluebutton/core/apps/chat/UserTypingPubMsgHdlr.scala

...ton/core/pubsub/senders/ReceivedJsonMsgHandlerActor.scala

...n/scala/org/bigbluebutton/core/running/MeetingActor.scala

...rg/bigbluebutton/client/meeting/AllowedMessageNames.scala

...n/scala/org/bigbluebutton/common2/msgs/ChatMessages.scala

...in/scala/org/bigbluebutton/common2/msgs/GoupChatMsg.scala

bigbluebutton-client/branding/default/style/css/V2Theme.css

.../org/bigbluebutton/modules/chat/events/UserTypingEvent.as

...src/org/bigbluebutton/modules/chat/maps/ChatEventMap.mxml

...bigbluebutton/modules/chat/services/ChatMessageService.as

...rg/bigbluebutton/modules/chat/services/MessageReceiver.as

.../org/bigbluebutton/modules/chat/services/MessageSender.as

...ent/src/org/bigbluebutton/modules/chat/views/ChatTab.mxml