Add trove classifiers for supported Python

Author: prmtl

setup.py

@@ -47,6 +47,11 @@ def get_version():
         'License :: OSI Approved :: MIT License',
         'Natural Language :: English',
         'Operating System :: OS Independent',
+        'Programming Language :: Python :: 2.7',
+        'Programming Language :: Python :: 3.4',
+        'Programming Language :: Python :: 3.5',
+        'Programming Language :: Python :: 3.6',
+        'Programming Language :: Python :: 3.7',
         'Programming Language :: Python',
         'Topic :: Scientific/Engineering :: Visualization',
         'Topic :: Software Development :: Libraries :: Python Modules'],