Block explicitely pyfaust.Faust fancy indexing when used in the both dimensions.

This point has been discussed in #50 comment 2.

v1, v2 two lists,
F[:,v2] # ok
F[v1, :] # ok
F[v1,v2] # error!

wrapper/python/pyfaust.py

@@ -796,6 +796,10 @@ class Faust:
                 elif(isinstance(indices[1], slice)):
                     out_indices[1] = indices[1]
                 elif(isinstance(indices[1], list)):
+                    if(isinstance(indices[0],list)): raise \
+                    Exception("F[list1,list2] error: fancy indexing "
+                              "on both dimensions is not implemented "
+                              "rather use F[list1][:,list2].")
                     if(len(indices[1]) == 0): raise empty_faust_except
                     out_indices[1] = indices[1]
                 else: