Moving an example from memoryviews.rst to the examples directory.

docs/examples/userguide/memoryviews/add_one.pyx

+import numpy as np
+
+def add_one(int[:,:] buf):
+    for x in range(buf.shape[0]):
+        for y in range(buf.shape[1]):
+            buf[x, y] += 1
+
+# exporting_object must be a Python object
+# implementing the buffer interface, e.g. a numpy array.
+exporting_object = np.zeros((10, 20), dtype=np.intc)
+
+add_one(exporting_object)

docs/src/userguide/memoryviews.rst

@@ -102,12 +102,9 @@ dimension::
    print(buf[-1,-2])
 
 The following function loops over each dimension of a 2D array and
-adds 1 to each item::
+adds 1 to each item:
 
-   def add_one(int[:,:] buf):
-       for x in xrange(buf.shape[0]):
-           for y in xrange(buf.shape[1]):
-               buf[x,y] += 1
+.. literalinclude:: ../../examples/userguide/memoryviews/add_one.pyx
 
 Indexing and slicing can be done with or without the GIL.  It basically works
 like NumPy.  If indices are specified for every dimension you will get an element