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:
pypa/setuptools#210. Basically, you get an
error about a failed parse when setup tools tries to rad the binary as
a Python or #! script :P

download-xflux.py

@@ -21,6 +21,7 @@ def download_xflux():
         tarchive = "/tmp/xflux.tgz"
         subprocess.call(['wget', url, '-O', tarchive])
         subprocess.call(['tar', '-xvf', tarchive])
+    subprocess.call(['chmod', 'a+x', 'xflux*'])
 
 if __name__ == '__main__':
     download_xflux()

setup.py

@@ -26,14 +26,15 @@
     ('share/applications', ['desktop/fluxgui.desktop'])]
 
 scripts = ['fluxgui']
+
 if (os.path.exists("xflux")):
-    scripts.append('xflux')
+    data_files.append(('bin', ['xflux']))
 else:
     print("""WARNING: if you are running 'python setup.py' manually, and not as
 part of Debian package creation, then you need to download the 'xflux'
 binary separately. You can do this by running
 
-    python ./download-xflux.py
+    ./download-xflux.py
 
 before running 'setup.py'.""")