- stop sharing from server side instead of destroing the applet from the client side

bigbluebutton-client/resources/prod/lib/bbb_deskshare.js

...bluebutton/modules/deskshare/managers/DeskshareManager.as

...bluebutton/modules/deskshare/services/DeskshareService.as

...gbluebutton/modules/deskshare/services/red5/Connection.as

...tton/deskshare/server/session/ISessionManagerGateway.java

...skshare/server/socket/BlockStreamEventMessageHandler.java

...ton/deskshare/server/sessions/SessionManagerGateway.scala

...ebutton/deskshare/server/sessions/SessionManagerSVC.scala

...bluebutton/deskshare/server/stream/DeskshareService.scala

...utton/deskshare/client/net/NetworkSocketStreamSender.java