Adding cython v0.20.2 in third-party.

third_party/cython/src/Cython/Plex/Timing.py

Index: third_party/cython/src/Cython/Plex/Timing.py
diff --git a/third_party/cython/src/Cython/Plex/Timing.py b/third_party/cython/src/Cython/Plex/Timing.py
new file mode 100644
index 0000000000000000000000000000000000000000..f47c5c89de7bfd3ebd9833a065edd99d5c4fef2b
--- /dev/null
+++ b/third_party/cython/src/Cython/Plex/Timing.py
@@ -0,0 +1,22 @@
+#
+#   Get time in platform-dependent way
+#
+
+import os
+from sys import platform, exit, stderr
+
+if platform == 'mac':
+  import MacOS
+  def time():
+    return MacOS.GetTicks() / 60.0
+  timekind = "real"
+elif hasattr(os, 'times'):
+  def time():
+    t = os.times()
+    return t[0] + t[1]
+  timekind = "cpu"
+else:
+  stderr.write(
+    "Don't know how to get time on platform %s\n" % repr(platform))
+  exit(1)
+