Update mate-control-center to 1.20.2:

Scale font DPI for HiDPI displays
Add support for HiDPI displays
theme-installer.c: missing g_object_unref in mate_theme_install_real
theme-util.c: fix reinstalling the deleted theme can cause failure
Support the theme compression package for installing XZ format
drop unused variables
eggcellrendererkeys.c: Fix build warnings:
remove some leftovers related to MacOS support
theme-thumbnail.c: Fix build warnings with write and pipe:
libslab: store search entry widget as GtkEntry
libslab: fix search icon misaligned
Translations update

(youri)