A11y themes in GNOME3

Hey,

I've spent some time yesterday working on the HighContrast.
LowContrast and Inverse themes. I thought I should post a quick note
about a11y themes in GNOME 3, so people know what things currently
work, what things don't, and where things live.

The Contrast control in the universal access panel sets both the gtk
theme and the icon theme to the same value, the options being
HighContrast, LowContrast and HighContrastInverse. The high contrast
switch in the universal access menu of the shell does the same (just
for HighContrast, obviously), as does the toggle-contrast keybinding
that is implemented in g-s-d. The meta-theme information in the
/usr/share/themes/≤theme>/index.theme files _is ignored_. When
metacity/mutter move to gsettings, we might consider adding the
metacity theme to the set of components that are set for Contrast. And
maybe it makes sense to tie the cursor and icon size to the text size
control, not sure. But for now, these theme components are not
affected at all, so if you want to need a different cursor theme or
size, you have to go directly to gsettings.

The a11y themes for gtk2 used to live in gnome-themes. They did not
really have matching icon themes and instead relied on setting stock
icons in rc files. Carlos has added a11y themes for gtk3 to
gnome-theme-standards last week. Yesterday, I have added gtk2 rc files
there too, and also created matching icon themes reusing icons found
in gnome-themes, mostly. This means that the three a11y themes that
are available from the universal access panel should work reasonably
for both gtk2 and gtk3. The icon themes are far from complete; help in
improving their coverage would be greatly appreciated.