Change 1 (of 2) : Frame with menus

Changed Frame so that pop up menus with the alternatives "New game" and
"Quit" appears when game is won or lost.

(Had to change the Game class, and the Frame constructor. Now the
WordList object is stored in Frame, and Game doesn't really do anything
except it creates a new Frame.)
Revert "Change 1 (of 2) : Frame with menus"

This reverts commit 8fe0e1eee43a4d420539da7ee656a10ef397bb99.