USAGE
./my_world -> start map editor
OPTIONS
-h print the usage and quit.
USER INTERACTIONS IN EDITOR MODE
CAMERA
UP / DOWN / LEFT / RIGHT -> move the camera
O / L / K / L -> change the camera angle
A / E -> change the camera zoom
Z / S / Q / D -> change the selected box on the map
BLOCKS
1 to 9 -> change the selected block type
W / X -> change the selection bar (+ / -)
SPACE -> Add selected block to selected box
G -> Remove a block on selected box
TERRAIN
R / T -> increase / decrease relief of selected box
