Drop typing dependency.

requirements.txt

@@ -1,11 +1,10 @@
 jsonschema==2.6.0
 aiohttp>=2.3.3,<2.4.0 # pyup: ignore
-aiohttp-cors>=0.5.3,<0.6.0 # pyup: ignore
+aiohttp-cors==0.6.0 # pyup: ignore; last version to support python 3.4
 yarl>=0.11
 Jinja2>=2.7.3
 raven>=5.23.0
 psutil>=3.0.0
 zipstream>=1.1.4
-typing>=3.5.3.0 # Otherwise yarl fails with python 3.4
 prompt-toolkit==1.0.15
 async-timeout<3.0.0 # pyup: ignore; 3.0 drops support for python 3.4

setup.py

@@ -49,6 +49,11 @@ setup(
     cmdclass={"test": PyTest},
     description="GNS3 server",
     long_description=open("README.rst", "r").read(),
+    setup_requires=[
+        # Environment markers were implemented and stabilized in setuptools
+        # v20.8.1 (see <http://stackoverflow.com/a/32643122/391865>).
+        "setuptools>=20.8.1"
+    ],
     install_requires=dependencies,
     entry_points={
         "console_scripts": [