What’s a national holiday celebrating the toils of the working class when you’ve got a 120,000-square-foot building to complete! This photo of work proceeding apace at developer Moshe Feller’s 107-unit, $32 million residential project at 23 Caton Place was sent in yesterday by a reader. Turns out, though, that while Feller may have been violating the spirit of the day, he wasn’t breaking any Department of Buildings regulations by having his laborers report to work. GMAP P*Shark DOB