allow icon only tab bar button (no text)

src/android/framework/TabBar.java

@@ -144,6 +144,7 @@ public class TabBar extends android.widget.LinearLayout implements
             ll.addView(iv);
         }
 
+        if (abb.label != null) {
             TextView tv = new TextView(themedContext);
             LinearLayout.LayoutParams tvp = new LinearLayout.LayoutParams(
                 ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT);
@@ -153,6 +154,7 @@ public class TabBar extends android.widget.LinearLayout implements
             tv.setTextSize(TEXTSIZE);
             tv.setText(abb.label.toUpperCase());
             ll.addView(tv);
+        }
 
         return ll;
     }