fix image paths in css

public/theme/css/default.css

@@ -180,7 +180,7 @@ a.zerobin {
   font-size: 12pt;
 }
 
-a.zerobin.create   { background-image: url('/img/pcreate.png');   }
-a.zerobin.download { background-image: url('/img/pdownload.png'); }
-a.zerobin.upload   { background-image: url('/img/upload.png');    }
-a.zerobin.latest   { background-image: url('/img/images.png');    }
+a.zerobin.create   { background-image: url('/theme/img/create.png');   }
+a.zerobin.download { background-image: url('/theme/img/download.png'); }
+a.zerobin.upload   { background-image: url('/theme/img/upload.png');    }
+a.zerobin.latest   { background-image: url('/theme/img/images.png');    }