Design a 3-bit Incrementer/decrementer
use btn_west as incrementer, i.e. when pressed, count increments by 1
use btn_east as decrementer, i.e. when pressed, count decrements by 1
use btn_south as reset, i.e. when pressed the count is resetted to 0.
use LD2, LD1 and LD0 to display count on the board. LD2 being MSB.
When count is 3'b111 and btn_west is pressed, it is reset to 3'b000.
When count is 3'b000 and btn_east is pressed, it is set to 3'b111.