resolution support fix/improvement

    * adding compatibility menu
    * backup gravity
    * set expanable=true if the screen size is hvga * density.
    * added "supports any density" mode. I'll add sdk check later.
    * disallow to catch orientation change event if the app is not expandable. This
      was causing layout problem under non-expandable mode. I discussed this with Mike C
      and we agreed to do this approach for now. We'll revisit if this causes problem to
      a lot of applications.