Add method to remove conversation from DeckAdapter by position

This makes the following patch to remove old conversations much more
efficient.

application/src/org/yaaic/adapter/DeckAdapter.java

@@ -172,18 +172,26 @@ public class DeckAdapter extends BaseAdapter
     /**
      * Remove an item
      * 
-     * @param channel
+     * @param position
      */
-    public void removeItem(String target)
+    public void removeItem(int position)
     {
-        int position = getPositionByName(target);
-
-        if (position != -1) {
+        if (position >= 0 && position < conversations.size()) {
             conversations.remove(position);
             notifyDataSetChanged();
         }
     }
 
+    /**
+     * Remove an item
+     * 
+     * @param target
+     */
+    public void removeItem(String target)
+    {
+        removeItem(getPositionByName(target));
+    }
+
     /**
      * Set single channel view
      *