Add GamePiece API to support stats.
Add stats display to the feed bag.
Add display stats to fry pan.

And, fixed a lurking bug/leak in the fried egg handling code.
Add farmer display stats.
Add display stats for chicken.
Add code to display stats on the game board.
Wire up all the game stats.
Wire up the farmer, add game over alert.
Keep hatched pullets as replacements

Keep the hatched pullets as replacements for dead hens. Wire up all the
remaining game notifications.
Restructure pullet code so it's testable and add tests.
Properly activate and dispose of chickens.
Remove stats when deallocating a game piece.
Show pullet stats.