it is inplace.

fail* functions are deprecated in Python 2.7.
Also remove reference to these deprecated functions from the doc.

test_scan2.py is just a copy of test_scan.py where the class is not an instance of unittest.TestCase anymore so that I can run tests with python instead of nosetests ( it helps when you want to add pdb breakpoints). I think that leaving it in the trunk is a bad idea though

'disable use of numpy.clip in perform mode as it don't handle correctly when the min is bigger then the max.'