Newspaper demo, Activity to Fragment part #1

+ Added some shiny assets in this commit.
+ Functional ArticleActivity using an ArticleFragment
   * url passed to fragment in bundle
   * fragment used to support future dual pane layout
   * TODO: either bump the min sdk version to 11 or make
     proper use of the support lib.

Next step, convert the ListActivity to a fragment, and create
the dual pane layout for tablets.