setup.py and MANIFEST.in: Make sure that PyPi is not missing the requirements.txt.

MANIFEST.in

+include requirements.txt

setup.py

@@ -21,6 +21,7 @@ setup(
     author_email='nils.brueggemann@mpimet.mpg.de',
     install_requires=install_requires,
     packages=find_packages(),
+    include_package_data=True,
     entry_points={
         'console_scripts': [
             'pyic_intake = scripts.pyic_intake:main',