Make 2D All Apps work better in landscape and on hdpi.

* Correct the density (or, rather, remove the density) of
  the icons in the cache to ensure they're drawn px-for-px.

* Create a new landscape layout for 2DAA that aligns things
  properly (viz: Home icon at right, padding tuned, 6
  columns).

* Performance improvement: Make the app grid, icons, and
  home icon all opaque (by setting a black background) and
  move the home icon so it doesn't overlap the grid.

Change-Id: I961323e9e39cb122cdc694853706e7fcdd10142f
4 files changed