Implement #1220212. Add os.kill support for Windows.

os.kill takes one of two newly added signals, CTRL_C_EVENT and
CTRL_BREAK_EVENT, or any integer value. The events are a special case
which work with subprocess console applications which implement a
special console control handler. Any other value but those two will
cause os.kill to use TerminateProcess, outright killing the process.

This change adds win_console_handler.py, which is a script to implement
SetConsoleCtrlHandler and applicable handler function, using ctypes.

subprocess also gets another attribute which is a necessary flag to
creationflags in Popen in order to send the CTRL events.
diff --git a/Modules/signalmodule.c b/Modules/signalmodule.c
index cecb2be..bb7e4b0 100644
--- a/Modules/signalmodule.c
+++ b/Modules/signalmodule.c
@@ -7,6 +7,7 @@
 #include "intrcheck.h"
 
 #ifdef MS_WINDOWS
+#include <Windows.h>
 #ifdef HAVE_PROCESS_H
 #include <process.h>
 #endif
@@ -793,6 +794,18 @@
     	PyDict_SetItemString(d, "ItimerError", ItimerError);
 #endif
 
+#ifdef CTRL_C_EVENT
+    x = PyInt_FromLong(CTRL_C_EVENT);
+    PyDict_SetItemString(d, "CTRL_C_EVENT", x);
+    Py_DECREF(x);
+#endif
+
+#ifdef CTRL_BREAK_EVENT
+    x = PyInt_FromLong(CTRL_BREAK_EVENT);
+    PyDict_SetItemString(d, "CTRL_BREAK_EVENT", x);
+    Py_DECREF(x);
+#endif
+
         if (!PyErr_Occurred())
                 return;