Bank coin state can get dorked

[MichelFloyd]

1. Player selects one or more coins
2. Player selects a card
3. Player purchases or reserves the card

Result: the coins they selected "disappear" from that player's view of the bank until the following turn when they reappear as if the user had just selected them. If another player had emptied one or more of the stacks of coins in question then the original player will get an error when they try to take those coins because they are not really there.

Suggestion: when a player selects a card, return all pending coins to the bank.