Fix icon painting transparency for the palette

Fix icon painting transparency for the palette

The icons shown in the palette do not have transparency applied to
them, which means that you end up with white squares on a white
background. This looks okay in the outline view where the icons are
shown on a white background, but it does not look good in the palette
where they are on a gray background.

This changeset fixes the icon generation a bit such that it records a
transparent pixel for these icons. It's not an ideal solution since we
only have on/off transparency, not an alpha channel, which means that
we can't have a smoothly anti-aliased edge of the circles regardless
of the background. Luckily, a light color seems to work fine for both
cases.

While I was at it I also adjusted the font positioning slightly on the
Mac platform for some letters that needed it.

Change-Id: Idf5a4f6709096935122bfe05cfecffc63e74a863