By Tzvi Machlin With Sean Payton announcing his retirement just a few days ago, the New Orleans Saints are getting a very late start to their head coaching search. But a few names are quickly emerging. According to ESPN NFL insider Adam Schefter, the Saints’ current head coaching candidates consists of three top candidates. Saints defensive coordinator Dennis Allen, Tampa Bay Buccaneers offensive coordinator Byron Leftwich and Detroit Lions defensive coordinator Aaron Glenn have all made the cut so far. Of the three, Allen is the only one with head coaching experience. He went 8-28 in 2.5 seas…