Adding cython v0.20.2 in third-party.

third_party/cython/src/Cython/Compiler/Future.py

Index: third_party/cython/src/Cython/Compiler/Future.py
diff --git a/third_party/cython/src/Cython/Compiler/Future.py b/third_party/cython/src/Cython/Compiler/Future.py
new file mode 100644
index 0000000000000000000000000000000000000000..671ccd13300911a23ffbb1bacc5d3f23888f277d
--- /dev/null
+++ b/third_party/cython/src/Cython/Compiler/Future.py
@@ -0,0 +1,14 @@
+def _get_feature(name):
+    import __future__
+    # fall back to a unique fake object for earlier Python versions or Python 3
+    return getattr(__future__, name, object())
+
+unicode_literals = _get_feature("unicode_literals")
+with_statement = _get_feature("with_statement")
+division = _get_feature("division")
+print_function = _get_feature("print_function")
+absolute_import = _get_feature("absolute_import")
+nested_scopes = _get_feature("nested_scopes")  # dummy
+generators = _get_feature("generators")  # dummy
+
+del _get_feature