Add animation the building process

[batmanovnn]

When the user has made a selection in the Building menu and clicked on the Build icon:

• change screen to city
• delay 0,5 second
• show red round on the place for this Build (opacity 50%)
• delay 0,5 second
• slow opacity change this Build from 100% to 0% (about 2 second)
• delay 0,5 second
• hide red round under this Build

[Areso]

Somewhat good idea, we discussed "building progress" thing with the other dev, but nobody of us could invest in the thing.
Though, may be we could do this as half-measure.