adding install_requires Cython for good measure

Author: proycon

setup.py

@@ -47,12 +47,13 @@
     author = "Maarten van Gompel",
     author_email = "proycon@anaproy.nl",
     description = ("Python binding to FROG, an NLP suite for Dutch doing part-of-speech tagging, lemmatisation, morphological analysis, named-entity recognition, shallow parsing, and dependency parsing."),
-    requires = ['frog (>=0.13.6)'],
     license = "GPL",
     keywords = "nlp computational_linguistics dutch pos lemmatizer",
     url = "https://github.com/proycon/python-frog",
     ext_modules = extensions,
     cmdclass = {'build_ext': build_ext},
+    requires = ['frog (>=0.13.6)'],
+    install_requires=['Cython'],
     classifiers=[
         "Development Status :: 4 - Beta",
         "Topic :: Text Processing :: Linguistic",