Add flags to Resume Saved game dialog

[ultrasquid]

Kind of says it in the title. When we start a new game, we are asked to select a flag for that game, in addition to giving it a name and selecting career or sandbox mode. But it is hard to come up with meaningful names to distinguish between saved games (for me anyway). The visual reminder of the flag would be helpful in selecting among saved games. So, I think adding flag icons to the saved games list would be a good improvement, using something we already have in a new way to make it better.