func Dir(dir string) Resources {
	_, filename, _, ok := runtime.Caller(1)
	if !ok {
		panic("failed to get Caller details")
	}
	dir = filepath.Join(filepath.Dir(filename), dir)
	return &resources{http.Dir(dir)}
}
Dir returns an Resources implementation that servers the files from the
provided dir location, it will expand the path relative to the caller.
package live
import (
	"io/ioutil"
	"net/http"
	"path/filepath"
	"runtime"
)
type Resources interface {
	http.FileSystem
	String(string) (string, bool)
}