Police say 21 people were killed in Tuesday's assault at upscale Nairobi hotel
Leaders have a three-year transitional period to put the country on a path toward peace and resettle IDPs and refugees
Lawmakers voted on constitutional changes that allow Kiir to stay in office until July 2021 and also extend their own terms and those of the country's governors
New round of peace talks is due to start next week in Addis Ababa
