With the existing background functions, single buttons can not be
styled separately - on the left side, the style of the left button
is picked, and the right button's style on the right side.
As theme authors may want to add rounded corners to button groups
as a whole, it makes sense to treat the case of a single button in
a group differently.
https://bugzilla.gnome.org/show_bug.cgi?id=635683
While the configured layout is taken into account for positioning
the buttons, the mapping from button function states to button
position states just assumed the default button layout in LTR
locales.
Do a proper mapping depending on the actual layout instead.
https://bugzilla.gnome.org/show_bug.cgi?id=635686
Frame types will form the bases of shadow classes, which are strings,
so export the to-string function so that we can do the conversion
uniformly.
https://bugzilla.gnome.org/show_bug.cgi?id=592382
Remove --allow-unprefixed option to the scanner, and fix resulting
problems:
* theme.h and boxes.h are split into a main -header and a private
header that includes stuff that is not generally useful and
hard to introspect. Merge theme-parser.h into theme.h.
* meta_display_get_atom() and meta_window_get_window_type_atom()
are marked as (skip)
* Fix annotation: (element-type Strut) => (element-type Meta.Strut)
https://bugzilla.gnome.org/show_bug.cgi?id=632494
