circleci.go
func (c *Client) ParameterizedBuild(account, repo, branch string, buildParameters map[string]string) (*Build, error) {
	opts := map[string]interface{}{"build_parameters": buildParameters}
	return c.BuildOpts(account, repo, branch, opts)
}
func (c *Client) ParameterizedBuild(account, repo, branch string, buildParameters map[string]string) (*Build, error) {
	opts := map[string]interface{}{"build_parameters": buildParameters}
	return c.BuildOpts(account, repo, branch, opts)
}
// ParameterizedBuild triggers a new parameterized build for the given
// project on the given branch, Marshaling the struct into json and passing
// in the post body.
// Returns the new build information