func (d MailDir) Filepath() (str string) {
	str, _ = filepath.Abs(string(d))
	return
}
get absolute filepath for this maildir
package maildir
import (
	"github.com/majestrate/bdsmail/lib/mailstore"
	"crypto/rand"
	"fmt"
	log "github.com/sirupsen/logrus"
	"io"
	"os"
	"path/filepath"
	"time"
)
type MailDir string