Implement new feature: set presentation downloadable on and off. Work in progress.

...tton/core/apps/presentationpod/PresentationPodHdlrs.scala

...esentationpod/SetPresentationDownloadablePubMsgHdlr.scala

...cala/org/bigbluebutton/core/models/PresentationPods.scala

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

...tton/core/record/events/SetPresentationDownloadable.scala

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

.../org/bigbluebutton/core2/FromAkkaAppsMsgSenderActor.scala

...org/bigbluebutton/endpoint/redis/RedisRecorderActor.scala

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

...org/bigbluebutton/common2/msgs/PresentationPodsMsgs.scala

...rg/bigbluebutton/modules/present/business/PresentProxy.as

...odules/present/events/SetPresentationDownloadableEvent.as

...g/bigbluebutton/modules/present/maps/PresentEventMap.mxml

...c/org/bigbluebutton/modules/present/model/Presentation.as

...luebutton/modules/present/services/PresentationService.as

...ton/modules/present/services/messaging/MessageReceiver.as

...utton/modules/present/services/messaging/MessageSender.as

...uebutton/modules/present/ui/views/PresentationWindow.mxml

...odules/present/ui/views/UploadedPresentationRenderer.mxml