- handle start and update of whiteboard shapes properly

.../conference/service/whiteboard/WhiteboardApplication.java

...org/bigbluebutton/modules/present/ui/views/SlideView.mxml

...button/modules/whiteboard/WhiteboardCanvasDisplayModel.as

...org/bigbluebutton/modules/whiteboard/models/Annotation.as

...t/src/org/bigbluebutton/modules/whiteboard/models/Page.as

...g/bigbluebutton/modules/whiteboard/models/Presentation.as

...igbluebutton/modules/whiteboard/models/WhiteboardModel.as

...bluebutton/modules/whiteboard/views/PencilDrawListener.as