handle fencepoint remove

def cmd_fence_remove(self, args):
        '''handle fencepoint remove'''
        if len(args) < 1:
            print("Usage: fence remove FENCEPOINTNUM")
            return
        if not self.have_list:
            print("Please list fence points first")
            return

        idx = int(args[0])
        if idx <= 0 or idx > self.fenceloader.count():
            print("Invalid fence point number %u" % idx)
            return

        # note we don't subtract 1, as first fence point is the return point
        self.fenceloader.remove(idx)
        if self.send_fence():
            print("Removed fence point %u" % idx)
        else:
            print("Failed to remove fence point %u" % idx)