- Modify Etherpad and SharedVideo so their resizing takes into account
  the width of the filmstrip in vertical filmstrip mode.
- Modify Filmstrip's getFilmstripWidth to account for when the filmstrip
  is hidden.
- modify VideoContainer so in vertical filmstrip mode it centers the
  shared desktop stream in the middle of the available space not taken
  by filmstrip.
- Also allow clickthrough on the secondary toolbar itself while still
  allowing clicks on the toolbar's buttons. This allows clicks on
  shared videos to go through.