ignore_aliases breaks with numy arrays

[barronh@…]

With all numpy arrays except type double, yaml crashes with error below:

TypeError?: data type not understood

steps to reproduce: python -c "import yaml; yaml.load(yaml.dump(arange(12, dtype = 'i')))"

steps to correct: patch yaml/representer.py using attached file

It appears that None and tuple or handled in a separate line from all other types. This can be avoided using the NoneType? from types.

Is there some other reason that these two are handled out of line?

By changing the implementation, numpy arrays of all types can be dumped.