The switcher windows aren't actually "active" per GTK's meaning because
they do not have actual keyboard focus, but they are controlled by the
internal grabs so it's effectively the same as if they were active.

Reporting them as such helps the ATs understanding what's going on.

Fixes #771.

When composited, the tab popup uses an OSD style which typically has a
dark background, so we use a light background highlight color.
However, when not composited the popup uses a light color and should
thus use a dark highlight.  This was done for the workspace popup, but
not for the window one, leading to the highlight being hardly visible
in several themes.

find . \( -name '*.h' -o -name '*.c' \) -exec sed -i 'N;/^\n$/D;P;D;' {} \;

find . \( -name '*.h' -o -name '*.c' \) -exec sed -i 's/[[:space:]]*$//' {} \;
find . \( -name '*.h' -o -name '*.c' \) -exec sed -i 's/\t*$//' {} \;

a dark color when compositing is disabled. Updates #566 which changed
the selected workspace to a light color on a light background.

When drawing the workspace switcher OSD, we want it to be slightly
transparent to match the OSD style. Also changed how the popup size is
calculated and changed window icons to cairo surfaces.

Instead of converting from surface to a GdkPixbuf and then back to
a surface, we keep it as a surface for the entire manipulation flow.
This improves rendering speed a bit and sets the ground for a higher
resolution thumbnail in the future.