Updated ExpandoHeaderControl sample for RC0

Here is the updated control sample for RC0.

 Just a few changes from Beta 2 - RCO:

  • generic.xaml needs to now be in a folder called "themes" (case sensitive) rather than in the root of your project. 
  • In VSM transition declarations "Duration" has been renamed to "GeneratedDuration"

So porting was easy.  If you want to play with this, definitely load it up in Blend and check out the great new VSM support as well.  It make re-templating MUCH easier and I had some fun creating weird collapse effects (not included).