Minimalist Tetris clone in OCaml.

Compile & run
$> make
$> ./tetris

controls: 
Q (or A)   : move left
D          : move right
W (or Z)   : rotate CW
S	   : rotate CCW
SPC (or F) : drop piece
TODO: 
- Add block preview
- Fix rotation algorithm
- Use a real timer (impossible with the graphic module)

DONE
- Delete completed lines
- Detect collision between blocks 
- Detect collision during rotation
- Add score
- Enable double buffering 
- Add game over detection
- Increase speed 

Author: Benjamin Negrevergne
License: GPLv3