update theano TUT

Author: Mofan Zhou

theanoTUT/theano5_function.py

@@ -25,7 +25,7 @@
 f = theano.function([a, b], [diff, abs_diff, diff_squared])
 print( f(np.ones((2, 2)), np.arange(4).reshape((2, 2))) )
 
-# name for a function
+# default value and name for a function
 x, y, w = T.dscalars('x', 'y', 'w')
 z = (x+y)*w
 f = theano.function([x,