River North&amp;#8217;s Mr. Beef Deli has been serving Chicagoans beef sandwiches for thirty years. Its walls, decorated with old and new album covers, movie posters and autographed celebrity photos, testify to both its age and enduring popularity. In a much-publicized crisis, Mr. Beef is facing foreclosure. Unable to get a new line of credit &amp;#8220;in [...]