Update support to python 3.5+ same as mkdocs

Author: timvink

setup.py

@@ -14,7 +14,7 @@
     author='Tim Vink',
     author_email='[email protected]',
     license='MIT',
-    python_requires='>=3.4',
+    python_requires='>=3.5',
     classifiers=[
         "Programming Language :: Python :: 3",
         "License :: OSI Approved :: MIT License",