The day after ABC pulled the plug on her No. 1 show over a racist tweet, Roseanne Barr returned to Twitter with a vengeance. The embattled comic hinted she may challenge the cancellation, tweeting to her fans Wednesday, "you guys make me feel like fighting back. I will examine all of my options carefully and get back to U [sic]." Barr created a firestorm this week when she posted a tweet likening former Obama White House senior adviser Valerie Jarrett to an ape. Barr originally said her tweet about Jarrett was "indefensible" and begged for forgiveness, reports CBS News correspondent...