Create a new Build instance.

        @param requests: a list of buildrequest dictionaries describing what is
        to be built

def newBuild(self, requests):
        """Create a new Build instance.

        @param requests: a list of buildrequest dictionaries describing what is
        to be built
        """
        b = self.buildClass(requests)
        b.useProgress = self.useProgress
        b.workdir = self.workdir
        b.setStepFactories(self.steps)
        return b