Move the popularity incrementation on idle
Move the popularity incrementation on idle

This function is taking a lot of time and doesn't need to
be run in sync.  Running it on idle restored performances
to levels similar to how they were before ChamplainCache was
introduced.

GNOME/libchamplain,GNOME/perl-Champlain,Distrotech/libchamplain,GNOME/perl-Champlain,potyl/champlain,Distrotech/libchamplain,StanciuMarius/Libchamplain-map-wrapping,PabloCastellano/libchamplain,Distrotech/libchamplain,StanciuMarius/Libchamplain-map-wrapping,PabloCastellano/libchamplain,potyl/champlain,Distrotech/libchamplain,GNOME/perl-Gtk2-Champlain,PabloCastellano/libchamplain,PabloCastellano/libchamplain,PabloCastellano/libchamplain,StanciuMarius/Libchamplain-map-wrapping,GNOME/perl-Gtk2-Champlain,StanciuMarius/Libchamplain-map-wrapping,potyl/champlain,potyl/champlain,Distrotech/libchamplain,StanciuMarius/Libchamplain-map-wrapping,GNOME/libchamplain