Add escape / close button to scenario selector

[Ushcode]

There is now a small x in the top right of the scenario selector

• This will only show up if a scenario has been selected at least once (so you can't skip it and have a map with no data)
• Also works to hit the esc key

• confirm px height of footer
• scenario escape

[gpeb2]

On my machine the scenario-header seems to overlap with the scenario-close button, see image. I've also made a minor point about code formatting.
Also would it be possible to either highlight the current scenario and/or make it clickable? I think adding a call to the close function when the scenario ID matches the current one, rather than just return would be enough. Or even just removing that condition all together.

[Ushcode]

On my machine the scenario-header seems to overlap with the scenario-close button, see image. I've also made a minor point about code formatting.
Fixed this.

Code should be there to show currently selected scenario in a darker colour but only one scenario currently up on hobbes to test