set python_requires metadata in setup.py (#109)

Signed-off-by: Matthew Peveler <matt.peveler@gmail.com>

Author: MasterOdin

setup.py

@@ -38,6 +38,7 @@
     ],
     setup_requires=setup_requires,
     version=version,
+    python_requires='~=3.5',
     classifiers=[
         "Development Status :: 4 - Beta",
         "License :: OSI Approved :: MIT License",
@@ -47,7 +48,6 @@
         "Operating System :: POSIX :: Linux",
         "Operating System :: MacOS :: MacOS X",
         "Operating System :: POSIX :: SunOS/Solaris",
-        "Programming Language :: Python :: 3.4",
         "Programming Language :: Python :: 3.5",
         "Programming Language :: Python :: 3.6",
         "Programming Language :: Python :: 3.7",