By CHRIS SHULL FORT WORTH — The Color Purple is a triple threat.The musical version of the novel by Alice Walker and movie by Steven Spielberg hit Broadway in December 2005. The North American touring company landed in Bass Hall for the first time Tuesday, bringing the sets, costumes and choreography of the original for a run through Sunday.The musical follows the trials and ultimate personal triumph of Celie in Georgia in the early 1900s.