Remove APK since preferred distribution is GitHub's release/tag mechanism.

Author: OMerkel

README.md

@@ -3,7 +3,7 @@
 
 * <em>Start an online</em> <b>UCThello</b> <em>session on</em> http://omerkel.github.io/UCThello/html5/src
 * <em>Also published in</em> <a href="https://marketplace.firefox.com/app/ucthello"><img align="middle" width="150px" src="https://marketplace.cdn.mozilla.net/media/fireplace/img/pretty/marketplace_logo.png" /></a>
-* <em>Android APK available for install</em> <img align="top" width="32" src="apk/android.gif" /> http://omerkel.github.io/UCThello/apk/ucthello-0.1.apk
+* <em>Android APK available for install</em> <img align="top" width="32" src="res/android.gif" /> https://github.com/OMerkel/UCThello/releases/tag/release_apk_0.1
     * requires minimum Android 4.4.2 (API-19)
 * <em>Runs in various browsers on</em>
     * <em>desktop systems like BSDs, Linux, Win, MacOS and</em>