code: public double getQualityOfMimeType (@Nullable final IMimeType aMimeType)
    {
      if (aMimeType == null)
        return QValue.MIN_QUALITY;
      return getQValueOfMimeType (aMimeType).getQuality ();
    }
docs: Return the associated quality of the given MIME type using the fallback
  mechanism.
  
  @param aMimeType
  The MIME type to query. May be <code>null</code>.
  @return 0 means not accepted, 1 means fully accepted. If the passed MIME
  type is <code>null</code>, the "not accepted" quality is returned.