Force clickable value

Hi,

First of all, I want to thank you for your hard work on this library, which is really useful and fills the drag/drop pattern gap on Android Sdk.

Days ago, I encountered an issue, using the drag-sort-listview : 
I made and set a custom adapter for a DragSortListView with a ayout file which was something like : 

        <?xml version="1.0" encoding="utf-8"?>
        <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
            android:id="@+id/wrapProg"
            style="@style/button"
            android:layout_width="fill_parent"
            android:layout_height="wrap_content"
            android:orientation="vertical"
             android:padding="4dp" >

             [.....]

         </RelativeLayout>


The drag/drop did not work, and I started to search why. I found that in my file styles.xml, the class "button" has a parent attribute set to "@android:style/Widget.Button"; which set clickable property to "true".
And that's why my code was not working as expected, so I set the clickable value of "button" class to false, and all work perfectly.

It's seems, that having dragSortListView with an item clickable, is pretty useless. That's why a made a fix, to set it programmatically on the library.

I hope my use case will help,

Julien