Speed up snake

We cannot speed up updating the display, but we can limit the updates to once a second, and take two steps per second.

buba/animations/snake.py

@@ -1,4 +1,5 @@
 import random
+from datetime import datetime, timedelta
 from time import sleep
 
 from buba.bubaanimation import BubaAnimation
@@ -46,6 +47,7 @@ class SnakeAnimation(BubaAnimation):
         self.body = [(x, y)]
         self.render()
         iterations = 0
+        last_update = datetime.now()
         while True:
             if self.is_blocked(x, y, d):
                 end = True
@@ -71,8 +73,11 @@ class SnakeAnimation(BubaAnimation):
                 self.grid[ty][tx] = 0
                 (tx, ty) = self.body[0]
                 self.grid[ty][tx] = 11
+            if datetime.now() - last_update > timedelta(seconds=1):
+                last_update = datetime.now()
                 self.render()
-            sleep(1)
+            else:
+                sleep(.5)
         sleep(5)
 
     @staticmethod