Update trove classifiers to current versions of Python

Author: cclauss

setup.py

@@ -23,10 +23,11 @@
             "Natural Language :: English",
             "Operating System :: OS Independent",
             "Programming Language :: Python",
-            "Programming Language :: Python :: 2.6",
             "Programming Language :: Python :: 2.7",
-            "Programming Language :: Python :: 3.2",
-            "Programming Language :: Python :: 3.3",
+            "Programming Language :: Python :: 3.4",
+            "Programming Language :: Python :: 3.5",
+            "Programming Language :: Python :: 3.6",
+            "Programming Language :: Python :: 3.7",
             "Programming Language :: Python :: Implementation :: PyPy",
             "Programming Language :: Python :: Implementation :: CPython",
             "Topic :: Games/Entertainment",