public static string Get(string svnuser)
{
if (gravatars == null || DateTime.Now.Subtract (retrieved).TotalMinutes > 10) {
gravatars = UserRepository.GetSvnGravatars ();
retrieved = DateTime.Now;
}
if (gravatars.ContainsKey (svnuser))
return gravatars[svnuser];
return svnuser;
}