More work on all icons to make sure they all match.

[Treblesteph]

Current status of each:

• [x] timer
  • happy with this one
• [ ] difficulty
  • could be an outline instead of filled shape
• [x] country game
  • very happy with this one
• [ ] capital game
  • almost happy, pillars look a bit thick though
• [ ] flag game
  • almost happy, slightly too thick, and maybe more rounded end of pole
• [ ] leader game
  • almost happy, slightly too thin, especially at the top of the crown
• [ ] dialling game
  • maybe too thick, or maybe lines too close to each other
• [ ] currency game
  • not happy with this one, needs even thickness of all lines, and rounded corners
• [x] language game
  • happy with this one I think
• [ ] timezone game
  • way too thick, but good rounded corners
• [ ] demonym game
  • too thin, but good icon
• [ ] area game
  • not sure, will see how it fits in when all others are done