circleci.go
func (c *Client) Build(account, repo, branch string) (*Build, error) {
	return c.BuildOpts(account, repo, branch, nil)
}
func (c *Client) Build(account, repo, branch string) (*Build, error) {
	return c.BuildOpts(account, repo, branch, nil)
}
// Build triggers a new build for the given project for the given
// project on the given branch.
// Returns the new build information