GLOBAL MARKETS-Shares rise after Scotland vote, Alibaba awaited

* Equities breathe sigh of relief after Scotland vote * World stocks head for fifth week of gains in six * Alibaba prices IPO at top of range, bolstering sentiment (Updates with open of U.S. trading; changes dateline; previous LONDON) By Ryan Vlastelica NEW YORK, Sept 19 (Reuters) - Stock markets around the world rose on Friday after Scotland voted to remain in the United Kingdom and removed an element of uncertainty for equity markets, which were on track for a week of strong