rea: remove debug output
fix: hunter thinks she has the gold if she just grabbed

Not shot!
rea: improve debug output
fix: calling Expedition.new with correct number of arguments
fix: gold-grabbing spec
mod: "wumpus found" means "wumpus location known and wumpus is alive"
add, fix: various fixes, specs

gold-grabbing remains in memory, Expedition stays inside the map
add: detecting a wall also means detecting the opposite wall
fix: Exploration specs
fix: Extermination stays inside walkable squares

It no longer tries to leave the walkable squares when trying to enter
the Wumpus' line of sight