Fixed filename of distutils-scripts on windows.

Unlike the console-script entrypoint scripts, the distutils
scripts didn't get a -script.py appended to their name on
windows. This is now fixed.
Cleaned up unused import and two unused variables
Added test for the fix I did for #53.
Merge pull request #53 from reinout/fix-distutilsscripts-on-windows

Fixed filename of distutils-scripts on windows. Fixes #52