_PY3_DATA_UPDATES uses win path if on win

py3_data function does not work on windows as the item would never match a value in a windows path.

_PY3_DATA_UPDATES now has a windows version if windows is used

This is only a quick fix as having the list of theses data directories is not perfect.
Merge pull request #777 from mad0house/py3fix-windows

_PY3_DATA_UPDATES uses win path if on win