Added animations to Discrete Bayes

Beginning of adding animations to the chapters. I wrote the
existing material not assuming animations, so it is quite
possible that I will want to revise the chapter to better
make use of this ability. For now I just animated two different
update/predict cycles.

code/bar_plot.py

@@ -7,16 +7,18 @@ Created on Fri May  2 12:21:40 2014
 import matplotlib.pyplot as plt
 import numpy as np
 
-def plot(pos, ylim=(0,1)):
+def plot(pos, ylim=(0,1), title=None):
     plt.cla()
     ax = plt.gca()
     x = np.arange(len(pos))
     ax.bar(x, pos)
     if ylim:
-        plt.ylim([0,1])
+        plt.ylim(ylim)
     plt.xticks(x+0.4, x)
     plt.grid()
-    plt.show()
+    if title is not None:
+        plt.title(title)
+
 
 if __name__ == "__main__":
     p = [0.2245871, 0.06288015, 0.06109133, 0.0581008, 0.09334062, 0.2245871,