(Photo by Gary Hershorn/Getty Images)Getty ImagesWeeks after floating a huge trial balloon, Comcast followed through this morning, announcing plans to spin off most of its linear cable networks into a separate company, including such stalwarts as CNBC, MSNBC, USA Network and SyFy.It’s the first tangible action among media executives who exulted in the days after the election about a more relaxed regulatory and M&A regime under the imminent Trump Administration. More importantly, the Comcast announcement lik ...