Add examples captchas.

README.md

@@ -1,5 +1,3 @@
-*TODO(dchest): Add example images and audio.*
-
 Package captcha
 =====================
 
@@ -9,6 +7,14 @@ Package captcha implements generation and verification of image and audio
 CAPTCHAs.
 
 
+Examples
+--------
+
+![Image](https://github.com/dchest/captcha/raw/master/capgen/example.png)
+
+[Audio](https://github.com/dchest/captcha/raw/master/capgen/example.wav)
+
+
 Constants
 ---------