Make setup.py runnable

@@ -13,7 +13,8 @@ def open_file(fname):
     return open(os.path.join(os.path.dirname(__file__), fname))
 
 
-setup(
+def run_setup():
+    setup(
         name='kappa',
         version=__version__,
         description='A CLI tool for AWS Lambda developers',
@@ -46,4 +47,7 @@ setup(
             'Programming Language :: Python :: 3.4',
             'Programming Language :: Python :: 3.5'
         ),
-)
+    )
+
+if __name__ == '__main__':
+    run_setup()