She's single! Tiffany Haddish and Common have ended their relationship after a year of dating, a source close to him tells E! News.  "It was an amicable split," the source shares. "They both still think very highly of one another, work obligations simply proved to be too much for them to move forward." He and Tiffany "ultimately decided to end things before continuing on with a long distance relationship," the insider adds, noting that Common will be in the United Kingdom for the next six months shooting a TV show. Tiffany, meanwhile, is in Atlanta filming a Disney movie with Owen Wilson for several months, according to a separate...