clean up ilastik-package

[k-dominik]

We still have a run_ilastik.bat file in our ilastik-exe package which runs ilastik by calling our python distro. But it does not a good job at isolating dll search folders, so on some system this might break (mkl might be the usual suspect). It has the benefit that you can also run the tests from an installation, but I haven't ever used it. It might be confusing for users to have it there, because our documentation often has linux/osx examples, and there the executable is called run_ilastik.sh. Maybe a rename could already resolve the problem... or we add a patched run_python.exe or something to achieve proper isolation.