Modify z-index values to more reasonable values
Display EditControls with a small delay on hover

It wil change anyway once we design a touch-compatible interface
Change delete icon to a bin icon
Add white border around arrows
Switch SlideVideoPlayer orientation depending on orientation
Have SlideVideoPlayer better fit small screens
Have the video/slide content centered vertically even on safari
Add shadow around thumbnails
Increase Transcript min height
Use more reasonable z-index definition for splitter handle
Do not submit annotations to the endpoint if the url is ""
Remove obsolete comment