Odd behaviors fix

Removed `onInterceptTouchEvent` override on `IndexableListView` class. It was producing some odd behaviors:

* Touching on items wasn't firing the flashing visual feedback on majority of times;
* Wasn't doing the "elastic" effect when scrolling out the list (tested on Samsung phone);
* If `areAllItemsEnabled` and `isEnabled` methods were overridden on custom `CursorAdapter`, the disabled items were ignoring all touch events (this prevented scrolling when `fling` started on disabled items).

It should be at least:

    @Override
    public boolean onInterceptTouchEvent(MotionEvent ev) {
        return super.onInterceptTouchEvent(ev);
    }

As it seems that this method isn't used for anything, I just dropped it.