add tokenize_rt to requirements

Author: spyoungtech

setup.py

@@ -19,7 +19,7 @@
     include_package_data=True,
     packages=find_packages("src"),
     package_dir={"": "src"},
-    install_requires=[],
+    install_requires=['tokenize_rt'],
     keywords=["async"],
     python_requires=">=2.7, !=3.0.*, !=3.1.*, !=3.2.*, !=3.3.*, !=3.4.*, <4",
     classifiers=[