Hi-DPI patches for 4.2

[Norbert Thiebaud]

On Mon, Mar 10, 2014 at 4:51 PM, Keith Curtis <keithcu at gmail.com> wrote:
> Doubling bitmaps is a "hack" but since bigger bitmaps don't exist, it
> is better than doing nothing.

The problem is that mac, in compatibility mode, already auto-double..
so we end-up with a quadrupling
of the bitmap, which mean you in the end only see a quarter of the
intended icon.