Move colorization to the display layer

Color output isn't necessarily always going to be a terminal output
thing, and terminals don't always support the same escape codes (e.g. on
Windows). Thus, all colorization efforts are done in the Display rather
than in the Game.

Signed-off-by: Alek Ratzloff <alekratz@gmail.com>

agame/__main__.py

@@ -2,10 +2,11 @@ import argparse
 import importlib.util
 from pathlib import Path
 import sys
-from agame.color import colorize
-from agame.display import ANSIDisplay
 from agame.game import Game
 
+# TODO - conditional import for this based on OS
+from agame.display import ANSIDisplay
+
 
 # Parse args
 parser = argparse.ArgumentParser(