Applies branch outtages.

def doOutages(self):
        """ Applies branch outtages.
        """
        assert len(self.branchOutages) == len(self.market.case.branches)

        weights = [[(False, r), (True, 1 - (r))] for r in self.branchOutages]

        for i, ln in enumerate(self.market.case.branches):
            ln.online = weighted_choice(weights[i])
            if ln.online == False:
                print "Branch outage [%s] in period %d." %(ln.name,self.stepid)