func (lens Lens) Header(artifacts []lenses.Artifact, resourceDir string) string {
	t, err := template.ParseFiles(filepath.Join(resourceDir, "template.html"))
	if err != nil {
		return fmt.Sprintf("<!-- FAILED LOADING HEADER: %v -->", err)
	}
	var buf bytes.Buffer
	if err := t.ExecuteTemplate(&buf, "header", nil); err != nil {
		return fmt.Sprintf("<!-- FAILED EXECUTING HEADER TEMPLATE: %v -->", err)
	}
	return buf.String()
}
func (lens Lens) Header(artifacts []lenses.Artifact, resourceDir string) string {
	t, err := template.ParseFiles(filepath.Join(resourceDir, "template.html"))
	if err != nil {
		return fmt.Sprintf("<!-- FAILED LOADING HEADER: %v -->", err)
	}
	var buf bytes.Buffer
	if err := t.ExecuteTemplate(&buf, "header", nil); err != nil {
		return fmt.Sprintf("<!-- FAILED EXECUTING HEADER TEMPLATE: %v -->", err)
	}
	return buf.String()
}
// Header renders the content of <head> from template.html.