EShellSettings predates GSettings and is no longer necessary.
GSettings allows binding GObject properties to GSettings keys,
with optional mapping functions. That fulfills the purpose of
EShellSettings.
GTK+ uses (G_PRIORITY_HIGH_IDLE + 20) for redrawing operations, which is
actually a slightly lower priority than G_PRIORITY_HIGH_IDLE. Therefore
for our purpose, G_PRIORITY_HIGH_IDLE is sufficient.
This reverts commit 2b507716b2.
The commit contains not a single comment as to why these custom priority
values are being used. The rationale needs to be documented in the code,
either at each call point or preferrably at a centralized priority value
definition.
Collect all the "config" extensions from the "addressbook", "calendar",
and "mail" modules into one place. These extensions typically just bind
GObject properties of extensible classes to app-specific GSettings keys.
