Recognise a new 'd' option in schema keys which gives a dictionary of
per-desktop default values. This dictionary is searched for the items
found in XDG_CURRENT_DESKTOP, in the order. If nothing matches (or if
the option is missing) then the default value is used as before.
This feature was requested by Alberts Muktupāvels and this patch is
based on an approach devised by them.
https://bugzilla.gnome.org/show_bug.cgi?id=746592
Add g_settings_schema_has_key() and _get_range(), _range_check(),
_get_value_type(), _get_default_value() methods on GSettingsSchemaKey.
Deprecate the equivalent APIs on GSettings.
https://bugzilla.gnome.org/show_bug.cgi?id=683017
Take this private API and make it public along with a boxed type and
ref/unref functions.
Future commits will add accessors with new functionality and some that
allow us to deprecate functions on GSettings itself (such as
g_settings_get_range).
https://bugzilla.gnome.org/show_bug.cgi?id=668232
These functions no longer have anything to do with GSettings itself, so
they should not be in that file anymore.
GSettings still wants direct access to the GSettingsSchemaKey structure,
so put that one in gsettingsschema-internal.h.
