Adding cython v0.20.2 in third-party.

third_party/cython/src/bin/cythonrun

Index: third_party/cython/src/bin/cythonrun
diff --git a/third_party/cython/src/bin/cythonrun b/third_party/cython/src/bin/cythonrun
new file mode 100755
index 0000000000000000000000000000000000000000..1c619549221a94a5e22ceb78faaae790a3e7e451
--- /dev/null
+++ b/third_party/cython/src/bin/cythonrun
@@ -0,0 +1,16 @@
+#!/usr/bin/env python
+
+"""
+Compile a Python script into an executable that embeds CPython and run it.
+Requires CPython to be built as a shared library ('libpythonX.Y').
+
+Basic usage:
+
+    python cythonrun somefile.py [ARGS]
+"""
+
+from Cython.Build.BuildExecutable import build, build_and_run
+
+if __name__ == '__main__':
+    import sys
+    build_and_run(sys.argv[1:])