Ellen DeGeneres gave one of the great, quirky vocal performances in animation history when she brought the daffy,, short-term memory-loss suffering Blue Tang “Dory” to life in “Finding Nemo.” And even though that film’s heart and narrative drive were in the hands of other characters, and even though there were plenty of scene-stealing supporting players in it, she swam off with the movie. Now, Pixar will at last cash in on Dory and make more use of Ellen with a sequel, “Finding Dory.” Still Swimming, after all these years. A holiday film (November) of 2015, Disney says.