add future package requirement

Author: bear

requirements.txt

@@ -1,2 +1,3 @@
+future
 requests
 requests_oauthlib

setup.py

@@ -40,7 +40,7 @@ def read(*paths):
                       read('AUTHORS.rst') + '\n\n' +
                       read('CHANGES')),
     packages=find_packages(exclude=['tests*']),
-    install_requires=['requests', 'requests-oauthlib'],
+    install_requires=['future', 'requests', 'requests-oauthlib'],
     classifiers=[
         'Development Status :: 5 - Production/Stable',
         'Intended Audience :: Developers',