A new generation of "Dallas" is headed for the airwaves. TNT says it is moving ahead with an updated version of the prime-time soap that aired on CBS from 1978 to 1991. The network announed Friday that the 10-episode season will be broadcast next summer. "Dallas" veteran Larry Hagman will be back at Southfork Ranch, as will his long-ago co-stars Linda Gray and Patrick Duffy. Hagman will reprise his role as villainous oil baron J.R. Ewing. Gray will again play J.R.'s wife, Sue Ellen, and Duffy...