Add wheel as test dependency

Author: atodorov

setup.py

@@ -24,7 +24,7 @@
     ],
     extras_require={
         'with_django': ['Django'],
-        'for_tests': ['django_tables2', 'factory-boy', 'coverage', 'pytest'],
+        'for_tests': ['django_tables2', 'factory-boy', 'coverage', 'pytest', 'wheel'],
     },
     license='GPLv2',
     classifiers=[