Move all logout and close events handlers from MainApplicationShell to new LogoutManager.

...ient/src/org/bigbluebutton/core/managers/LogoutManager.as

...src/org/bigbluebutton/main/events/ExitApplicationEvent.as

.../src/org/bigbluebutton/main/maps/ApplicationEventMap.mxml

...g/bigbluebutton/main/model/users/NetConnectionDelegate.as

...rc/org/bigbluebutton/main/views/MainApplicationShell.mxml

...on-client/src/org/bigbluebutton/util/i18n/ResourceUtil.as