[GLib] Added missing OrderedSet:IsEmpty ().
[GLib] Added CodeExporter:AddClientsideFunction (), CodeExporter:AddClientsideFunctions (), CodeExporter:AddClientsideFile (), CodeExporter:AddClientsideFiles (), CodeExporter:AddClientsideIncludeFile (), CodeExporter:AddFinalizedClientsideFunction () and CodeExporter:AddFinalizedClientsideFunctions ().