What Hulu giveth, Hulu taketh away. At first applauded for its openness in providing its content to other distributors, the online streaming video company — a joint venture of NBC Universal and News Corp. — this week pulled back that content from Web-to-TV software provider Boxee and TV.com, CBS’s digital video service. However, CBS is now pushing back at Hulu, and those rumblings you hear on the digital horizon may be the first shots fired in a new round of major media company battles over the right to watch TV shows on your computer.