Make the app UI less reliant on shades of different color

[squeak9]

I have trouble telling green and red apart sometimes, especially in small details. I noticed the shop editor uses icons that are pretty small and are either red or green and this is a bit hard to make out sometimes.

It looks pretty obvious for this huge screenshot but its a different story on your phone. One easy way to fix this could be to have the background change from black to white or something?

One easy way to check if a UI has any color issues like this is to try to use the app in grayscale mode. You can do this on android phones in the developer options (look for monocromancy) and in windows 10 by searching for "color filter" in the start menu. This will make any color issues clear.

I know the amenity view mode is all color based so that's trickier but fixing this example above is a good start at least.

[Zverik]

Relevant to #51.