Update requirements

requirements/requirements.txt

@@ -1,4 +1,7 @@
+enum34;python_version<"3.4"
+ipaddress;python_version<"3.3"
 mbstrdecoder>=0.2.2
 python-dateutil>=2.6.1
 pytz>=2017.2
+setuptools>=20.2.2
 six>=1.10

setup.py

@@ -27,20 +27,11 @@
 with open(os.path.join(REQUIREMENT_DIR, "requirements.txt")) as f:
     install_requires = [line.strip() for line in f if line.strip()]
 
-if any([
-    sys.version_info.major < 3,
-    sys.version_info.major == 3 and sys.version_info.minor < 4,
-]):
-    install_requires.append("enum34")
-
-if any([
-    sys.version_info.major < 3,
-    sys.version_info.major == 3 and sys.version_info.minor < 3,
-]):
-    install_requires.append("ipaddress")
-
 with open(os.path.join(REQUIREMENT_DIR, "test_requirements.txt")) as f:
-    tests_require = [line.strip() for line in f if line.strip()]
+    tests_requires = [line.strip() for line in f if line.strip()]
+
+with open(os.path.join(REQUIREMENT_DIR, "docs_requirements.txt")) as f:
+    docs_requires = [line.strip() for line in f if line.strip()]
 
 needs_pytest = set(["pytest", "test", "ptr"]).intersection(sys.argv)
 pytest_runner = ["pytest-runner"] if needs_pytest else []
@@ -61,8 +52,12 @@
     license="MIT License",
     long_description=long_description,
     packages=setuptools.find_packages(exclude=["test*"]),
-    setup_requires=[] + pytest_runner,
-    tests_require=tests_require,
+    setup_requires=pytest_runner,
+    tests_require=tests_requires,
+    extras_require={
+        "test": tests_requires,
+        "docs": docs_requires,
+    },
 
     classifiers=[
         "Development Status :: 3 - Alpha",