GLOBAL MARKETS-Shares rise modestly, set for strongest week since July 2013

* Microsoft gain lifts U.S. shares * Ebola scare limits U.S. gains, weighs on Europe stocks * U.S. Treasuries prices edge higher on Ebola fear * Euro rises against dollar on short-covering (Adds U.S. market open, changes byline, dateline; previous LONDON) By Sam Forgione NEW YORK, Oct 24 (Reuters) - Global equity markets rose modestly on Friday as gains in Microsoft buoyed U.S. shares, even as news that a New York City doctor tested positive for the Ebola virus produced a m