Update setup.py for Python 3
Update setup.py for Python 3

Apparently you can no longer install arbitrary binaries using
`scripts`. Instead you need to use `data_files` now.

Discussion of error in Python 3 when trying to use `scripts` to
install binaries here:
https://github.com/pypa/setuptools/issues/210. Basically, you get an
error about a failed parse when setup tools tries to rad the binary as
a Python or #! script :P

xflux-gui/xflux-gui