changed book icon back to the old, more identifiable one
added back the forum icon to the tab, was having trouble getting
  minimizing to work properly... needs more investigation
moved from dim/show click handlers to a toggle - works properly
  since we mutate instead of replace the dim/show button
fixed condition where if you clicked show before moving off a dimmed
  post, the force-dim class wouldn't be removed
changed name to "Forum Extension" on popup