TODO.txt

Bugs:
  - when pressing "space" or "escape", the key event is propagated to the underlying page
    (I currently call only preventDefault. Should I call stopPropagation() too?)
    (despite event.stopImmediateProgation() being called!)

Maybe later:
  - Allow easy customization of default WPM
  - Move-back-a-word (shift left/right)
  - Question mark ('?' to show help)
  - Something about hyphenated-words-which-are-shown-too-shortly
  - Progress bar:
    - CSS animation for smoothness?
    - Allow clicking/dragging to change position
    - Automatically increase height as mouse get closer for easier access
  - Option to install as Grease/TamperMonkey script
    (requires fixing `@run-at context-menu` bugs!)
  - Sentence preview when seeking?
  - Option to alternate between RSVP/regular text? (Perhaps on pause?)
    This would also help when seeking.
  - Embed HTML/CSS in the bookmarklet for easier editing?
    The widget is fixed, so there is no real need to build its DOM tree
    dynamically, and inserting literal HTML/CSS would be easier to customize.
    (Just define a few "special" element ids or CSS classes to find the right
     divs to update.)
  - Mobile support? (Requires all functionality is available by tapping or
    dragging, without the need for a keyboard.)