functions to return all neighbors added; need BFS to determine whether each square is on an island
pieces follow real gravity
gravity working, but need to check for rows after
rows clear after gravity takes effect
replaced BFS with DFS in isIsland function making more performant
replaced BFS with DFS in isIsland function making more performant
going to make changes to implement variable timing
game speeds up every 10 rows
game working with scoring, on-deck piece, level
separated into multiple files saved on global Tetris namespace
refactored board class; decoupled functions