def request_is_from_mobile?
      @request_is_from_mobile ||= 
        request.format.to_sym == self.class.mobile_format || 
        IsItMobile.mobile?( request.env['HTTP_USER_AGENT'].to_s, request.env['HTTP_ACCEPT'].to_s )
    end
def request_is_from_mobile?
      @request_is_from_mobile ||= 
        request.format.to_sym == self.class.mobile_format || 
        IsItMobile.mobile?( request.env['HTTP_USER_AGENT'].to_s, request.env['HTTP_ACCEPT'].to_s )
    end
Checks if the request.format is *already* @@mobile_format (set by the
 query string or using an extension of 'mobile' with resourceful routes)
 and if not, uses IsItMobile.mobile? to determine whether or not the
 request is from a mobile device