Population popup animation and shop arrow

Two new visual improvements to the game:

1. Population/points popup animation
   Each time you place or merge a house a little points animation shows above. Maybe I'll limit the appearance rate of single popups later if I feel it's to nervous. What do you think? Do you like it?
2. Wobbling arrow above the shop button
   I didn't like the size animation of the button. Now it's just flashing red and a little arrow display for some seconds. Maybe I'll change it to only display until the shop was first time entered. Not yet sure.