Climbing level and end-of-game

[don't] don't insist on players grabbing "GO" to start playing. Pressing START anytime on the menu screen should work as well. [done] update LEDS so that it crops out-of-boundary monsters when saving -- that should be easier than at loading.[done] unit-test SEDS components and figure out what corrupts .spr files when editting[need] show number of …