[18] Quiz questions give simple positive feedback immediately.

[norbu09]

• User is shown two available coins on quiz question load
• Each time they get an answer wrong, one of the coins greys out
• Each time they get an answer correct, the coin moves (w. animation) to the next available slot in their coin row
• If they run out of coins or get the correct answer, they are moved on to the next question

[eoinkelly]

Done.