Create an option window to add the show FPS option

[hteumeuleu]

Currently, the FPS counter can be toggled on or off by doing a full crank turn. In practice, though, it only needs to hit the zero degree threshold of the crank, which is when the crank is upwards. So just moving the crank left and right from zero is enough to trigger the FPS counter.

Ideally, we should have a proper options screen (akin to the assist mode one). It would be triggered by a new “options” menu item replacing the current “fullscreen” check. The option screen would then feature the following options:

• Fullscreen:on/off
• Show FPS:on/off