/// <summary>
/// Returns the previous site and adds the current site to the
/// next sites stack.
/// </summary>
/// <param name="currentSite">The current site of the browser</param>
/// <returns>Previously visited site</returns>
public string ReturnPreviousSite(string currentSite)
{
string previousSite = PreviousSites.Pop();
NextSites.Push(currentSite);
return(previousSite);
}
