TODOs:
- convert into HTML
- maybe display inside a R77 specific help dialog (from Command dialog)
- check if Command dialog and Settings shoud use the same button (16:9,4:3)
- explain Command and Settings dialog
- explain Power-on options dialog (or refer to Stella User's Guide)

*** Navigation ***

Stella can be controlled via the console buttons or a joystick in left or
right port.

Inside Launcher:
  Joystick   Button     Action
  --------------------------------------------------
  Up         SAVE       previous game
  Down       RESET      next game
  Left       LOAD       page up
  Right      MODE       page down
  Button     SKILL P1   start selected game
  Button #2  SKILL P2   open Power-on options dialog
  -          COLOR,B/W  open Settings dialog

Inside a dialog:
  Joystick   Button     Action
  ----------------------------------------------------
  Up         SAVE       change/increase current option
  Down       RESET      change/decrease current option
  Left       LOAD       previous dialog element
  Right      MODE       next dialog element
  Button     SKILL P1   select
  Button #2  SKILL P2   cancel
  -          4:3,16:9   previous tab
  -          FRY        next tab

During emulation:
  The joysticks work normal and all console buttons as labeled except of the
  following.

  Button     Action
  ----------------------------------
  4:3,16:9   open the Command dialog
  FRY        return to Launcher

Note: If you have a keyboard attached via OTG all keys work as described in
the Stella User's Guide.