Update registry search paths for python interpreter find module
As of 3.6.1 Python (only version tested in this case), installing 32-bit
version on 64-bit windows has a slightly different registry key path.
-32
is appended to the end of the version number in the path. Also added
a few more registry path guesses based on 64-bit version of Python.
Also the module now checks if the host is WIN32 instead of the target, which is required if you are cross compiling.
Topic-rename: FindPythonInterp-3.6-windows