Fix a bug: pyfaust.Faust.__getitem__() returns a Faust when indexing an element F[i,j].

- Modify getitem unit test in consequence.
It closes #33.

misc/test/src/Python/test_FaustPy.py

@@ -203,7 +203,7 @@ class TestFaustPy(unittest.TestCase):
         # test one random element
         rand_i, rand_j = self.r.randint(0,self.F.shape[0]-1),self.r.randint(0,self.F.shape[1]-1)
         if(prod[rand_i,rand_j] != 0):
-            self.assertLessEqual(abs(self.F[rand_i,rand_j].todense()[0]-prod[rand_i,rand_j])/abs(prod[rand_i,rand_j]),
+            self.assertLessEqual(abs(self.F[rand_i,rand_j]-prod[rand_i,rand_j])/abs(prod[rand_i,rand_j]),
                                  10**-6, msg=("compared values are (ref,rest) ="
                                               +str(prod[rand_i,rand_j])+str(prod[rand_i,rand_j])))
         # test one random row

wrapper/python/pyfaust.py

@@ -635,6 +635,8 @@ class Faust:
         elif(isinstance(indices, tuple)):
             if(len(indices) == 2):
                 out_indices = [0,0]
+                if(isinstance(indices[0], int) and isinstance(indices[1],int)):
+                    return F.todense()[indices[0],indices[1]]
                 if(indices[0] == Ellipsis):
                     if(indices[1] == Ellipsis):
                         raise IndexError('an index can only have a single ellipsis '