Landscape mode

[ghost]

On Android it does not rotate to landscape

[roughike]

This is currently disabled on purpose since I didn't have time to look into doing a good landscape layout.

For this to land, it would be nice to:

• [ ] use Slivers to show/hide the app bar when scrolling
• [ ] on showtimes page, show/hide the date selector as well when scrolling
• [ ] see that every other screen looks good.

I'll see if I get someone else to request this feature, and if so, I'll raise the priority to medium.