static string TryTermInfoDir (string dir, string term )
{
string path = String.Format ("{0}/{1:x}/{2}", dir, (int)(term [0]), term);
if (File.Exists (path))
return path;
path = Path.Combine (dir, term.Substring (0, 1), term);
if (File.Exists (path))
return path;
return null;
}