Add requirements.

This is preliminary only.

setup.py

@@ -13,6 +13,8 @@ setup(
     author="Frank Scholz",
     author_email='coherence@beebits.net',
     license = "MIT",
+    install_requires = ['Coherence', 'Twisted', 'setuptools', 'pygame',
+                        'Louie', 'osso', 'Image | PIL'],
     packages = find_packages(),
     scripts = ['bin/compere'],
     url = "http://coherence.beebits.net",