By Lin Noueihed and Maggie Fick CAIRO (Reuters) – Supporters of Egypt’s deposed president will stage a “Friday of martyrs” of mass protests, risking more potential bloodshed to show they can still claim the streets after a week in which hundreds were gunned down and their leaders jailed. Egyptians are enduring the bloodiest civil unrest of their modern history after the military overthrew Mohamed Mursi on July 3 following demonstrations against his rule. …