Some smaller UI changes and else:

- added play video button for better lefthand support
 - wrote codepart to darkon5s listitem improvements
 - set minimum api level to 15 (Android 4.0.3 support)
 - updated to sdk level 23 including the new support libs

app/src/main/res/values-sr/strings.xml

@@ -1,3 +1,4 @@
+<?xml version="1.0" encoding="utf-8"?>
 <resources>
     <string name="app_name">Јутјуб цев</string>
     <string name="title_videoitem_detail">Јутјуб цев</string>