[GUI] Some precisions in the world chart are broken

[RESTRICTED ACCOUNT]

I noticed that the precision of some graphs in the chart tab of citylist has been broken.
Specifically, jobs and three transportation achievement rate graphs.
This was caused by merged from the standard by ranran - I apologize for the lack of checking.
The fix for this is included in pull request #468.

[jamespetts]

Excellent, thank you: now incorporated.