Switch app icons to non-"beta" versions

[gnprice]

As part of launching the app beyond beta, we'll want to switch the app icons to the designs we have which don't say "beta".

For details, see:

• logo: Use new design, and support fancy Android features #1404

  Specifically, see the section at "To get the non-beta versions" in the comment logo: Use new design, and support fancy Android features #1404 (comment) .