fix #52

If PyStand.exe is attached to a console, then show error message in the console.

PyStand.cpp

@@ -341,10 +341,12 @@ const char *init_script =
 "    fp = os.fdopen(fd, 'w')\n"
 "    sys.stdout = fp\n"
 "    sys.stderr = fp\n"
+"    attached = True\n"
 "except Exception as e:\n"
 "    fp = open(os.devnull, 'w')\n"
 "    sys.stdout = fp\n"
 "    sys.stderr = fp\n"
+"    attached = False\n"
 #endif
 "for n in ['.', 'lib', 'site-packages']:\n"
 "    test = os.path.abspath(os.path.join(PYSTAND_HOME, n))\n"
@@ -359,6 +361,8 @@ const char *init_script =
 "    code = compile(text, PYSTAND_SCRIPT, 'exec')\n"
 "    exec(code, environ)\n"
 "except Exception:\n"
+"    if attached:\n"
+"        raise\n"
 "    import traceback, io\n"
 "    sio = io.StringIO()\n"
 "    traceback.print_exc(file = sio)\n"