Update README.md

Author: msn0

README.md

@@ -3,7 +3,7 @@
     <img width=122 height=71 src="https://raw.githubusercontent.com/msn0/teti/master/teti.png" alt="teti" />
     <br>
     <br>
-	<img width=606 src="https://raw.githubusercontent.com/msn0/teti/master/screencast.gif" alt="teti screencast" />
+	<img width=606 src="https://raw.githubusercontent.com/msn0/teti/master/screencast-teti4.gif" alt="teti screencast" />
 	<br>
 </h1>