v0.3

Several concepts were added to the game, such as money, and research.

With the economic system, you have to build power stations more carefully because it needs money. And the source of money is the consumption of cities, the more you provide, the more they consume, the more you earn. 

When the cities need more and more, power stations will always provide not enough power, then you need to do some research to improve the capacity of a single power station or reduce the waste of power lines.

Besides, UI and other stuff has been modified.

With these features, the game seems to be more challenging, hope you enjoy it.