Index out of bounds when notifyDataSetChanged() is called.

Hi there, I'm currently working with a ```ListView``` and a ```Cursor``` using this library. 

All works fine but when i try to change my adapter's cursor and notify that the content has changed, the ```AdapterView``` calls ```SectionedBaseAdapter.getItemId()``` (from ```AdapterView.rememberSyncState()```) with ```position = 0```, so the ```getPositionInSectionForPosition(0)``` call returns -1.

So, since ```AdapterView``` will **always** call that method with position 0 (and no one else), I just made this simple little hack.