initial captioning client commit

bigbluebutton-client/build.xml

bigbluebutton-client/src/CaptionModule.mxml

...utton/modules/caption/assets/Closed_captioning_symbol.svg

...uebutton/modules/caption/events/GetCaptionHistoryEvent.as

...tton/modules/caption/events/ReceiveCaptionHistoryEvent.as

...tton/modules/caption/events/ReceiveNewCaptionLineEvent.as

...ebutton/modules/caption/events/RequestTranscriptsEvent.as

...ebutton/modules/caption/events/SendNewCaptionLineEvent.as

...ebutton/modules/caption/events/StartCaptionModuleEvent.as

...uebutton/modules/caption/events/StopCaptionModuleEvent.as

.../bigbluebutton/modules/caption/managers/CaptionManager.as

...g/bigbluebutton/modules/caption/maps/CaptionEventMap.mxml

...src/org/bigbluebutton/modules/caption/model/Transcript.as

...rc/org/bigbluebutton/modules/caption/model/Transcripts.as

.../bigbluebutton/modules/caption/services/CaptionService.as

...bigbluebutton/modules/caption/services/MessageReceiver.as

...g/bigbluebutton/modules/caption/services/MessageSender.as

...rg/bigbluebutton/modules/caption/views/CaptionWindow.mxml