Minor refactoring, started working on rotation
Very simple rotation system (transpose), doesn't check if can_rotate (yet)
Refactoring, and piece moves down once at each turn regardless of what is going on (i.e. can't block it against a wall)
Added hard drop, undo pieces falling down at every turn (see previous commit), renamed pieces.py to block.py
Updated .gitignore (removed TODO -- now in global .gitignore)
Changed block representation
Added line removal at each round. Kind of looks like a Tetris now