Absolute to Relative path - From http://stackoverflow.com/questions/13266756/absolute-to-relative-path and http://stackoverflow.com/questions/703281/getting-path-relative-to-the-current-working-directory/23697173#23697173
public string GetRelativePath(string filePath, string referencePath)
{
var fileUri = new Uri(filePath);
var referenceUri = new Uri(referencePath);
var relativeUri = referenceUri.MakeRelativeUri(fileUri).ToString();
var relativePath = relativeUri.Replace('/', Path.DirectorySeparatorChar);
return relativePath;
}